There may be some value in a long gestation for a book as for an individual. First, the resulting offspring usually is more viable at birth and, second, the father has more time to contemplate the conception, morphogenesis, and future. While we will all judge this book’s viability for ourselves, it may be fruitful to share some of my contemplations.
The selection of any set of contributors to a book or symposium, of necessity, involves a prejudicial process. My biases were admittedly multifaceted. Over all, an attempt was made to select investigators that would provide, first and foremost, work or an approach among the salient areas of development in reproduction and sexual behavior, and which could be considered significant in expanding horizons of study or serving as points of departure for future work. Further, the implicit intention was to present in addition to basic research data, material which would be projective or even speculative and thus not overly diminished by the time span of a few years. This selection wasn’t simply a matter of choosing topics and then selecting suitable authors, or choosing the authors and leaving the topics open. An interplay of both was involved. For the program participants, also considered was the relationship of the investigator, or his work, to that of William C. Young, those considered closely aligned getting the first available spots. For the volume, however, no such restriction was imposed. To all these criteria of mine were added the predispositions and personal bent of each contributor. The resulting publication is thus, despite all initial resolve, the sum of all these parts. Dealing primarily with what we have rather than what we might have had, the following insight is offered.
Many of the investigators selected could equally as well have been requested (although they may not have been so willing) to write on other topics being handled in the volume. This capacity which at first seemed remarkable, turned out on closer consideration to be a matter of necessity for the researcher and is in itself testimony to the broad yet interwoven applicability of much herein. For the field of reproduction and sexual behavior an expert in one particular area is ever finding himself wed to developments and advancements in other areas of the overall field. Very narrow specialists are rare. Bibliographies to practically all the papers contain references to work by several of the volume’s contributors and it should simultaneously be noted that more than half have themselves written or edited books covering many categories in this field. The import of this becomes more readily appreciated when it is realized that the organization of specialties within the study of reproduction are arbitrary and often encompass wide latitudes. For example, one who wishes to keep thoroughly abreast of developments and theories of ovulation and menstruation keeps abreast as well with related theories of estrogen and progesterone action. Similarly, one who tries to understand the influences of neonatal or prenatal endocrines on adult behavior must know about hypothalamic differentiation, and to fully appreciate brain–pituitary–gonad interactions, one must understand the basic parameters of brain investigation techniques. Many more cross-author (cross-chapter) links can be listed and are evidence of this overlapping interest. In this vein it is probably safe to say that each contribution interacts and has value and context with others presented, although the chapter titles may at first glance indicate otherwise. For the reader who approaches this volume via one particular chapter further reading is thus encouraged. This overall selection of papers should, it is hoped, signal increased breadth to the research encompassed by studies in reproduction and sexual behavior. Significantly, aspects of basic molecular endocrinology and enzymology are seen linked to features of molar behavior and physiological processes are inexorably related to entities as seemingly divergent as season, experience, and genetics. To researchers caught in the bind of already having too much to master in their immediate area, this may serve as a necessary stimulus (or threat) to at least maintain an acquaintance with developments in related peripheral areas.
Included and considered not only appropriate but necessary for representative coverage are works related to themes which, to some, may appear quite diverse and unrelated or of little importance. Criticisms may occur for the choice of areas emphasized as well as those excluded. This is probably inevitable and perhaps warranted. What will be reemphasized thereby is that the borders used to delimit the area of “necessary” coverage are amorphous or nonexistent. (It also parenthetically reflects, to some extent, those fields which are getting the most encouragement, and those which have sufficient numbers of qualified investigators so that marked developments plus suitable and available authors could be found.) On a most basic level, it may be easier to state that the fundamental themes of reproduction and sexual behavior are different entities than to find the dividing line between them or their conjoined boundaries. At one time refuge was sought by claiming that sexual behavior could occur without reproduction but not vice versa. The use of artificial insemination and ova transplants, however, quickly show this futile. In addition, one cannot fully argue against the “expressed desire to reproduce” by a woman, even via artificial insemination, being a manifestation of sexual behavior! I will defend the absence of a firm definition for these basic terms by claiming that this would limit our area of purview and be unduly restrictive; any loose definition would be too vague to be useful.
The difficulty in selecting acceptable definitions for the broad categories and areas exist as well for all operational terms. This is probably no more or less true for reproduction and sexual behavior than for any other discipline, but the remainder is timely. As is so often the case, frequent use of certain words lead to a sense of security with their meaning and the fact that they are being used as jargon is lost. Jargon has its place when terms are operationally defined and is defendable as being communicative to all those using the terms. Professional isolation or parochialism, however, perpetuates the use of idioms without their concomitant limits or awareness that serious issue might be taken with “basic assumptions.” Words represent ideas and ideas per se can become jargon, meaning different things to different people. One investigator’s basic assumptions and obvious axioms are not necessarily held true by other investigators. Exposure of these differences alone should initiate a valuable dialogue. It is noteworthy and a mark of experience that in the course of elaborating on concepts most of the authors have taken care to define the terms they use, probably having met other acceptable definitions which are thus routinely anticipated.
We might consider some definitions our authors have chosen or assumed. Everett defines the pseudopregnant situation for the rat and mouse as a progravid state primarily under the control of prolactin synthesis and release and indicates this gonadotropin’s relationships with a functionally maintained corpus luteum, decidual reaction, and vaginal condition. The necessity for this extensive definition is justifiable and reinforced by Nalbandov et al.’s caveat that prolactin may be without effect on the extended life span of corpora lutea in species other than laboratory rodents and that distinction should be made between luteotropic and steroidogenic effects. With examples of clinical eases with which we can all readily identify, Noyes goes to great lengths to define various reproductive conditions usually considered only on the black or white basis of fertility versus sterility. With a novel twist for a scientist, he suggests we include with our definition of eufertility a value judgment which may fluctuate depending upon whether it is society’s or the individuals’ values that are adhered to, and would “include the needs of the race as well as the individual.”
Some terms, however, have not been defined but assumed understood by past repeated usage and general acceptance. Unfortunately, these words may have acquired connotations which are not universally accepted. For example, Masters and Johnson discuss the sexually “inadequate” couple. Impotence, frigidity, and premature ejaculation are considered as detrimental clinical conditions which the “inadequate” couple wants to change. While definitely advocating and agreeing with giving aid to those seeking help, we may simultaneously conceive that for some couples active sexual relations may be undesirable or harmful. Behavioral treatment processes for such individuals may beneficially impose impotence or frigidity. “Inadequacy” then, just as sterility, may be advantageous or desirable for some couples.
Intuitive assignments or normal and abnormal and natural and unnatural are ever with us; perhaps more so with sexual behavior studies than in others. For studying nonbehavioral reproductive processes and mechanisms investigators may proceed relatively unhindered by personal value commitments to the outcome of the work as well as its mode of investigation. Not only can all phases of contraception be examined but lately even abortificants for all stages of pregnancy are receiving attention and study. Although adverse pressure indeed comes from some quarters, e.g., religious, this too is rapidly changing. Encouragement for study, on the other hand, is heard from groups as divergent as farmers and breeders interested in the economic fallout of such work, clinicians and patients faced with an undesirable situation, and demographers and eugenicists concerned with the future of mankind. This enviable situation is reflected in the comparative availability of funds for studies of even small links in the chain of reproduction. It must be said that the freedom was hard won transcending many taboos and cultural injunctions.
Studies of sexual behavior regrettably are still a long way from such free and open inquiry, not only among the laity but among professional personnel as well. Conditioned by society’s injunctions or previous scientific training we may each have to watch the intuitions and taboos within ourselves. Consider the following: Beach has examined mounting phenomenon both as a male and as a female characteristic. In practically all species studied both sexes display the patterns not only heterosexually but homosexually. Yet many of our colleagues, academic as well as clinical, professional as well as lay, will persist in considering this behavior abnormal for a female, particularly in regard to analogous behaviors seen in the human. As suggested by Beach, Whalen, Phoenix et al., and myself in this volume, we might think of male–female behavior differences in terms of relative frequencies: i.e., males usually mount females more often than females mount females and females lordose more often than males, but females may mount females and males may lordose. Aronson and Cooper have reported how season and peripheral sensitivities may interact to effect male mating performance in the cat. Yet the claim is still often voiced that males are always “ever-ready.” Undoubtedly, for the male as for the female, consideration must be given to multiple peripheral and external factors of which we are only slowly becoming aware. Bronson has indicated how urinary pheromones effect estrous and nidation in the female mouse. Can we still persist in considering the estrous cycle or implantation as relatively inviolate? Whalen reviewed the effect of neonatal hormone treatment for rats; Phoenix, Coy, and Resko discussed prenatal endocrine effects on primates; and I presented some comparable material for humans. The reviews seem to leave no doubt that pre- or neonatal endocrine conditions can structure adult sexual behavior. Yet many will still deny the probability that humans too may be so effected. Obviously the more we learn the more we can, and probably should, reexamine basic concepts, intuitions, and ideas long considered axiomatic.
One plea is repeatedly voiced or intimated by our authors, be they primarily biochemists, morphologists, endocrinologists, or behaviorists—more comparative information from diverse species is needed before generally applicable laws or axioms in reproduction or sexual behavior can be validly formulated. Comparisons are sought at every level of the reproductive process from biochemical to behavioral. From comparative data, Hafez probes the working of uterine enzyme systems while Villee and Williams-Ashman and Shimazaki study mechanisms of hormone action. From different species Cole asks how the gonadotropins function, Zarrow et al. study the role of progesterone in reproduction, and Nalbandov et al. question how corpora lutea are maintained. Bronson checks strain and specie differences in vaginal cycles and olfactory responses, and Beach looks at comparative mounting behavior. With increasing cross-specie comparisons, all preach caution in generalizing from species to species without adequate data. Mossman beautifully demonstrates diversity with such (who can yet really say extreme) examples as the elephant shrew, which ovulates an average of sixty eggs yet only implants two, and the human, which ovulates and implants only one. Which should we take as our model? Are we justified in taking the rat as our universal standard just because we probably know most about this species? Information being garnered from others indicates we may, with increased knowledge, select as a model species one with reproductive processes more consistent with different norms.
From various animal groups the distilled similarities and uniformities will provide us with the most applicable guides. The moral then is clear—we need more data from more species. The frequent repetition of this theme is a loud admission of ignorance from those best qualified to profess knowledge. Even more significant is the fact that this cry has repeatedly been voiced for some time now. Beach in 1950 (American Psychologist, 5: 115-124) wrote a classical paper on this topic particularly pertinent to behavior and Mossman in 1945 with Hamilton and Boyd incorporated this thesis in the text Human Embryology. Why hasn’t the cry been answered? Why the species gap? Somehow relative scientific values considered in terms of return for investment of time, effort, and funds seems to enter here. Interspecific differences are often seen as a deterrent to further research rather than a stimulus. Is it “better” to find out more about the reproductive process in one species or more about a particular phase in several species? Would a comparative study of ovulation in the mongoose, bat, and porpoise (all mammals), or the chicken, turtle, and camel (all vertebrates) return as much information as readily as an in-depth study of ovulation in any one species? Since most investigators do not do comparative work, the answer to these types of questions would appear to be negative. But this may be a function of lack of facilities, lack of peripherally related information, and general reluctance to run the gamut of non-problem-related complications which this type of study entails. It may also reflect the biases of funding agencies to “keep to proven paths.”
Distilled from the pleas described above and the actual work of many of our authors, however, is the suggestion that compiling and working with comparative data rather than being scientific-dilettantism may actually lead to the core of some of the presently most vexing enigmas. Further, an intriguing set of additional problems are thus set for unveiling and interpretation, e.g., differences and similarities between reproduction in induced and spontaneous ovulators, short- and long-lived species, seasonal and perennial breeders, domestic and wild animals, nocturnal and diurnal species, and so forth.
A Model System
Several authors indicate that for their particular subjects much information but little knowledge exists. Simultaneously encyclopedic reviews or experiment oriented papers without extensive extrapolations or general statements are included in the volume. Nevertheless, the preceding chapters do record notable advances in our knowledge. This is especially obvious if we, for certain points, synthesize the enumerated factors to be considered for total appreciation and selectively incorporate negative information as well. In the main, optimism rather than pessimism should prevail. For example, a good deal of attention has been focused on the interplay of the hypothalamus, pituitary, gonads, and end organs as related to reproduction and sexual behavior. Consider how practically every author has presented some new insight or material pertinent to mechanisms which serve to regulate these physiological or behavioral processes. With primary emphasis on the role of the brain, Sawyer devotes his whole chapter to this problem of feedback mechanisms. The synthesis and release of pituitary gonadotropins is reviewed as controlled by the action of target-organ gonadal steroids working via direct influences on hypothalamic and hypophyseal centers. With experimental evidence from brain and pituitary steroid implants, electrical lesioning or recording, both positive and negative feedback influences are presented. In addition, indications are given that we must also consider an internal “short-loop” direct feedback action of LH on the hypothalamus which is independent of its influence on classical target organs.
Everett in his discussion of “delayed pseudopregnancy” characterizes many of the endocrine and neural interactions pertinent to this subject but significantly contributes to the overall picture of “feedback” by emphasizing what we can term a “long-loop” circuit. This is manifest by stimuli, copulatory or experimental, which are otherwise neutral in immediate endocrine effects but can set in motion reproductive events that lead to activation of corpora lutea at some later time.
Nalbandov, Keyes, and Niswender, without using the expression “feedback,” discuss such factors in the regulation, function, and maintenance of corpora lutea. With particular emphasis on the gonadotropins, they show by comparative data that we need consider not only the biochemical nature of the tropic substance but its mode of and signal for release. They emphasize in this regard that special distinction need be given to whether the sex steroids themselves and the gonadotropins are acting as steroidogenic or luteotropic agents.
Scharrrer adds to our knowledge of feedback at the crucial linkage points of the nervous and endocrine systems. The separation of the systems may facilitate some studies, but the classical dichotomy is seen here as anachronistic. She places particular focus on dual-capacity neurons, i.e., those “cells that are capable of receiving nervous stimuli and of dispatching hormonal messages to endocrine centers.” This type of integrative system is of significance not only in reproduction and reproductive behavior but is of concern to behaviorists of all stripes. (The interaction of the nervous and endocrine systems now taken so much for granted in endocrine studies is without a doubt among the most significant relationships crucial not only in understanding reproduction but in fully comprehending how an organism can respond to his environment. For all biologists and psychologists it provides a link for unifying external events with internal processes. For behaviorists the ramifications for understanding other physiologic-psychologic processes are rapidly becoming better appreciated.) Catecholamines are also discussed by Scharrer (and Whalen as well) as representing another category of neurosecretory hormones whose role in reproductive processes and control is yet to be fully realized and demands further study.
While the authors mentioned have probed what may be happening within the brain, Lisk contributes considerably to our knowledge on feedback systems by detailing the techniques available for further studying exactly where within the brain neural centers for the control of these phenomena may be localized.
“Control” at the target organ is stressed by such authors as Cole, Reynolds, and Mossman. These investigators provide data and questions pertinent to uterine and ovarian function and embryo–mother relations as well. Questions are posed in regard to the threshold levels of PMS needed to maintain pregnancy in the mare, the stimulus for estrogen on progesterone production by follicular cells, the functional relation of the uterine cervical ganglion to parturition, and the absence of feedback manifest by a nonallergic response between mother and embryo.
Pineus and Dorfman and Rooks are obviously concerned with feedback mechanisms, since the most promising contraceptive measures they mention other than via physical barriers work via alteration in one or another physiological control system. The various contraceptive pills and steroid preparations obviously fall in this category but the IUD too probably works by altering a normal feedback chain.
Hafez, Villee, Bishop, Williams-Ashman, and Shimazaki contribute to understanding control process from a molecular and biochemical viewpoint. Not only are the active moieties, be they enzymes or hormones, to be considered, but so too are the substrate or receptor sites, which themselves may be active or passive. These studies point up the very probable situation that at this ultramicroscopic level a multiplicity of feedback types may need be considered rather than an inclusive all-purpose control.
In contrast with the work and authors discussed above which may be considered to relate to feedback problems as more classically viewed in endocrinology, the following authors contribute insights on regulatory mechanisms from a behavioral perspective.
Aronson and Cooper review central mechanisms pertinent to arousal and sexual performance and bring special attention and stress to peripheral factors which mediate copulation. Not only are genital sensory stimuli per se seen to be crucial, but they are seen to interact with internal rhythms and seasons of the year. In this particular instance, however, the oddity is that the relation is more highly correlated in the desensitized males. In normal males the penile feedback is capable of overriding seasonal influences which tend to decrease sexual behavior.
Beach reviews various factors, internal and external, which are involved in mounting behavior by female mammals and stresses how species differences, even within the same order, are seen to be crucial considerations. Guinea pigs and rats, for instance, differ in their mounting responses to estrous and nonestrous stimuli females. Bronson shows that not only species but strains within a species may vary in sensitivity to various feedback factors. Witness his forceful demonstration that the innate estrous cycles of the C57 BL/6J and 129/J mice are mediated differently by male urine.
And it is now recognized from the work reviewed by Whalen, Phoenix et al., and myself that the various control systems involved both in reproduction and sexual behavior, at neural and endocrine responsive end-organ levels as well, may be organized pre- or neonatally to bias the feedback regulatory mechanisms seen in the adult and that this bias may be experimentally or naturally induced. With data from rodents, primates, and humans, we are in an enviable situation of having cross-species data which appears consistent in support of an endocrine-influenced developmental theory relative to the ontogeny of sexual phenotypes, mammalian sexual behavior, and reproductive conditions.
By amalgamating most of the above considerations, we came upon a view (Fig. 1) of the individual being subject to internal and external feedback factors which are responsive to stimuli at all levels. For some readers the figure may appear too general to be of use. To others, however, it will provide a clearer view of the complexities involved and possibly serve as a model for understanding other highly integrated disciplines. Certainly if nothing else, the figure emphasizes how an interdisciplinary view of a problem may indicate crucial factors for consideration. The total picture of this puzzle still lacks definition, but pieces are constantly being added and the outlines are being clarified.
We can repeat then that, for reproduction in general, optimism rather than pessimism is warranted. Basically we now know that in regard to physiologic as well as behavioral processes species may be expected to vary. These differences may exist in the biochemical and physiological mechanisms of related gonadotropin, steroid and enzyme actions. We now know that seasonal, situational, and peripheral conditions as well as tonic, genetic, and central phenomenon may influence reproductive and behavioral processes. Equally of importance we now have defined much of what we still need to know and most important we now know that the solution to problems in an area of physiology may provide the answers needed in an area of behavior and vice versa. Lest these be taken as inconsequential advances or banal truisms, reflect for a moment on the available data and relative status as a discipline of any other interacting biologic process and behavior pattern, e.g. the autonomic-adrenal system and aggression or the digestive system and feeding or drinking behavior. No other comparable discipline seems so well situated. (This may be an appropriate point to advocate the formation of a distinct discipline of Sexology and restore to good graces the title of avocation “sexologist.”)
It is obvious that the hypothetical dichotomy between molar and molecular as bad versus good science is within a volume such as this more than amply dispelled for the study of reproduction. Discussions of mounting phenomena or mechanisms of sexual arousal or theories or molecular and enzyme action are equally scientific, basic, and valuable. Research on the degeneration and regeneration of the dorsal nerve of the penis is on a par with studies of seasonal variation in libido. And the comprehension of neurosecretory cell mechanisms is a challenge which only in technique and interest differs from the intellectual and scientific processes involved in analyzing problems in sex-role ontogeny or the methods by which homosexuals cope with their problems in society. The comprehension and appreciation of pheromonal mechanisms requires equal parts of behavior study and biochemical procedures. The role of progesterone is analyzed as a behavior-mediating, physiology-mediating, or molecular-activity-mediating hormone, and the actual biochemical structure of the androgen involved in sexual differentiation is being sought by the same individuals observing the behavior. Not only then do behaviorists and biochemists work on the same problem, but both molar and molecular problems are often studied simultaneously by the same behaviorists or biochemists.
Similarly, the line between pure and clinical research as good versus bad science is seen to be arbitrary when we realize how often they are the same, how much they interrelate, and how much we can learn from each about basic mechanisms. A great deal is seen exposed and in need of further clarification from the “applied” studies by Masters and Johnson on techniques for altering sexual behavior patterns, the contraceptive methods discussed by Pincus or Dorfman and Rooks, the considerations on fertility enumerated by Noyes, or any of the many programs mentioned by Gebhard.
For example, Masters and Johnson claim rapid success in altering basic behavior patterns which no doubt in many cases developed over several years. Surely this brings to question the learning process, role of reinforcement, and status of “insight” in altering supposedly intractable human behavior. In addition, it calls to question those portions of sex play and copulatory methods which might be reversible and those which might be irreversible. The report of Dorfman and Rooks most probably reflects on some of the gonadotropin control mechanisms discussed by Sawyer, Everett, and Whalen, but the mysterious actions of the IUD reawaken us to the fact that we still lack a full understanding of egg transport, implantation, and uterine physiology. And Gebhard, probably because he covers so many types of studies, in progress or needed, certainly links pure and clinical research in a multitude of areas. Indeed, it seems a poor value judgment that condemns a study just because the results or methods do or do not apply primarily to humans. Consider, as an example, that it is not only animal behaviorists but human behaviorists as well which attempt to distinguish and separate those mechanisms that arouse individuals to sexual behavior from those mechanisms actually used in the performance of the behavior. This dichotomy has taken on new emphasis in the human, but the associated parameters have been an active area of research in animal studies for some time now. In the past it was generally assumed that an individual once “aroused” would “act.” As indicated by Gebhard, however, we still lack data on the arousability of even items such as hard-core pornography, and statistical correlation of this arousability with behavior is nonexistent. Nevertheless, this material is condemned. On the other hand, we also have scant knowledge of the effects of sex education programs, but these are highly touted and increasing in number and scope. Understanding of these clinical and social questions regarding sex will give us better insight to the basic mechanisms sought in the laboratory and may likely reveal processes we don’t yet know exist. In addition, the laboratory findings will no doubt help provide practical clinical and social approaches now unthought of. Both are mutually contributory and scientifically informative.
Technique and Approach
The criteria for good versus bad or pure versus applied science should rest on approach and rigor rather than techniques and goals. If a study or question is pursued using faulty technique, it is bad, regardless of whether it uses observational criteria or a spectrophotometer. If a study has proper controls and well-defined parameters, it may be scientifically good whether the outcome will satisfy only curiosity or satisfy a need. The techniques used do not per se determine scientific value or validity.
A further word is in order with regard to techniques. The general approaches to endocrine, physiological, and biochemical processes of interest are basically classic and standard. Much value is seen in the repetition of crucial studies in several laboratories and the repeated use of standardized methods. Much of value has also come from the judicial selection or design of new or seemingly bizarre methods. Along with classic surgical techniques which are well represented, Nalbandov et al. utilize X rays for the selective destruction of ovarian follicles without loss of the luteal or interstitial tissue. Along with the tissue culture techniques, biochemical and histochemical methods used by Hafez, Villee, Bishop, and Williams-Ashman and Shimazaki, single-cell investigation methods are used by Scharrer. But noticeably missing from any of our authors’ experimental reports is one of the least appreciated techniques, which may, however, be the most rewarding—constant observation. It is assumed that statistically sampled observations are as valid a source of data as constant observation. One wonders, nevertheless, if Young and co-workers had taken that course if the nuances of guinea pig behavior and associated endocrine conditions would have revealed themselves as graphically. Dempsey thinks not and I would tend to agree.
Owing to the significance and presently extensive use of brain investigative procedures, Lisk had been asked to discuss this methodology specifically. He reveals multiple uses of the various techniques and relates them to the types of information thereby obtainable. Sawyer and Everett in their chapters amply demonstrate the types of data garnered by such methods.
Techniques should be considered not only as modes of operation but also as modes of approaching and thinking about a problem. This recent focus on the nervous system and shift away from the reproductive organs per se is a sign that as a result of a “new technique” and new approach, yet unchartered areas for exploration and means of studying reproduction have been opened.
Several chapters adequately demonstrate how biochemical techniques play a role in understanding reproduction and sexual behavior by providing solutions to immediate problems. For example, Bronson can seek and find the urinary components which serve as sexual attractants or pregnancy blocks and Nalbandov et al. can more definitively probe which portion of a gonadotropin complex acts as a luteotropic agent. Exposure to the more general and more abstract biochemical theories and mechanisms, however, once unraveled, could eventually be infinitely more valuable by providing a new conceptual dimension—possibly sufficient enough to usher in a shift away from the present emphasis on the nervous system in reproduction studies. Several examples will make my meaning clear. When Everett talks of a long-delayed response, will studies show us that cellular biochemical reactions are taking place which may require this time and thus account for the delay or will the delay be found in extensive reverberating neural circuits? When Beach talks of species differences in mounting behavior, what portion of these differences are to be accounted for by intraneural or membranous biochemical events and which to interneuronal arrangement? Will Bishop’s ideas and techniques of biochemical “fingerprinting” be of use in answering these types of questions?
The fact that animals differ in hormone levels, as graphically mentioned by Cole, may not be an index of what the animal needs for efficient reproduction, but may reflect enzyme systems which nullify the differences by having the same turnover rates, or presenting a common limiting number of appropriate receptor sites; manifestation of the differences may similarly be restricted by the amount of preformed proteins available for mobilization at any one time.
And if a good number of contraceptive agents seem to depend for their efficacy on estrogens, is this related to the hormones effect to stimulate growth rates, alter processes, or initiate new reactions otherwise dormant or absent? While Phoenix et al. are concerned with whether testosterone or another metabolite is active at the differentiating tissues or I am in a quandary regarding the nature of F.M.T.S., it basically may be more significant to know if the “organization” to which we refer is encoded within a genome, is the expression of genes encoded in the mitochondrial or nuclear DNA or both, and whether the mitochondria and nuclei are independently regulated by the hormones. Further, it is highly significant to know “whether the molecular processes which underlie expression of the ‘organizational’ actions … be recapitulated whenever the ‘activational’ effects of these hormones take place.”
The investigator who mentally synthesizes the molar questions being asked throughout the book with the molecular concepts and data presented, or possible of being extrapolated from the chapters with biochemical orientations, cannot help but be impressed with the possible theoretical implications not only for understanding reproductive processes but much in biology at large.
Predictably, as a technique and mental approach, behavioral methods will continue to expand their influence in providing new insight into reproductive processes at all levels. The methods used for behavioral analysis may seem less standard than those used in classical biology and deserve some special comment. In few areas does imagination in the development of new measures seem so rewarding and so ever present. Zarrow, Brody, and Denenberg evaluate the weight of nesting material used by a rabbit and the amount of loose hair picked up by combing. They find that these measures not only correlate with pregnancy, but are interrelated with survival of young. Aronson and Cooper record direction and physical approach of a male cat and find this related to his copulatory success and capable of telling us something significant about orienting mechanisms for coitus. Whalen reports on adult rat mating behavior correlated with a single neonatal steroid injection. Phoenix, Coy, and Resko record chases and fights among monkeys and show that genetic females, if prenatally treated with androgen, will show prepubertal behavior more like males than females. While the parameters of these test situations might seem arbitrary, they are carefully chosen, stated, and controlled, and interpretations made therefrom are cautiously offered. Each new technique provides a means of asking a different and unique set of questions and presents new perspectives for evaluating old questions. While the results may be recorded in bizarre units, e.g., mounts, or grams of wood shavings, for all biological disciplines, behavioral studies are usually among the most stringent in the use of statistics. The information finally gained is no less valuable to reproductive studies than if garnered by more biologically “orthodox” ways. In this regard, particular attention is called to the criteria for a 5-year follow-up imposed by Masters and Johnson for judging treatment efficacy. This is an exemplary caution, particularly for clinical behavior studies, and is the type of requirement which is long overdue.
Among the several suggestions of importance and applicability to all reproductive scientists made by our authors, I would like to single out and emphasize one. Mossman considers the wealth of material routinely discarded by investigators themselves or at their retirement or death and unused due to an institution’s lack of storage space and means for proper cataloging and distribution. All too often an individual’s life work and scientific collections are disposed of while still capable of yielding valuable data and serving as fertile source material. It would indeed seem a wise investment for an agency, private, philanthropic, or governmental, to arrange for the acquisitioning, accessioning, and use of such collections. There are myriads of tissue specimens collected and preserved for one specific analysis or question which are still good for various other types of studies. Perhaps a repository for such material could be established by the Public Health Service under the auspices of the National Institute of Child Health and Human Development. There may even be sufficient interest for a private institute to accept such collections. Raw data of all sorts if properly identified may also be included with the tissue collections, but if primarily of behavioral interest may be collated at a separate institute. If drawn from and used, it is anticipated many dollars would be saved in nonduplication of these preparations or collection efforts and the service cannot help but provide an inestimable saving in time. Particularly for those on low budgets or with specific needs, original source material of an immense variety would thus be made available for study. With proper attention to credits where due, an individual may thus continue to reap scientific kudos even after death or retirement. This is indeed an idea worthy of consideration as donors to, users of, or custodians for such collections.
Philosophy and Prophesy
All contributors were encouraged to present crucial problems and questions in need of solution and express their impressions as to the significance, implications, and future for the findings they reviewed. The authors presented questions rather freely and repeatedly provided intriguing scientific challenges. I consider this one of the features of the book. On the other hand, not all the authors took the opportunity to prophesize or philosophize and few chose to openly speculate. This may be because it is naturally quite difficult to meaningfully forecast the future, but more likely it is because by training researchers are taught to be cautious; they know all too well that today’s truths and theories often become tomorrow’s fables, and they are conditioned by journal editors who tend to discourage philosophy and speculation in scientific reports. This conservatism is a necessity for accumulating reliable and consistent data and ensuring that hypotheses and constructs are not taken for fact. This same conservatism, however, becomes a liability for instigating original or new lines of research. Biology, as one of the oldest experimental sciences, rooted in the tradition of the laboratory and correctly eschewing theory without data, to my mind, suffers from this concomitant dearth of cogent speculation and freely offered hypothesis. Assuming that within any discipline those of its members best familiar with the field are most able to point the way for future directions and present lifetime challenges, it is imperative we not only give license to speculate with greater freedom but we encourage it. This increased freedom and responsibility must include the right to be wrong in presenting problems as significant, suggesting courses of action, or making predictions. The resulting occasionally misplaced efforts notwithstanding, it is anticipated that many years and tears of needlessly waiting for the proper zeitgeist would be thus bypassed. Taking this as a personal mandate, I here offer the following forecasts extrapolated from the writings and questions posed within the previous chapters and colored with my own perspective.
Direction, Scope, and Techniques
Reproduction studies, as all biology in general, will become increasingly dependent upon interdisciplinary behavioral, physiological, structural, and biochemical—and multilevel—molar and molecular—techniques for its significant developments. From the present emphasis on the role of the brain and its generalized control functions, effort will expand in three main directions. First, peripheral tissues and sensory mechanisms, spinal level processes, and the environment itself will be investigated to account for many of the individual variations seen. Simultaneously, evaluation of all processes will increase in scope longitudinally to consider differences throughout the individual’s life and cross sectionally to consider changes during courtship, copulation, pregnancy, etc. Second, the organization of biochemical, physiological, and behavioral patterns from stimuli of any type, e.g., genetic, endocrine, or environmental, will be further explored. An ideal experiment soon will show how a crucial set of cells is altered (genetically?) to effect responses different from those seen without the stimuli. Not only prolonged exposures but even transient events, if severe enough, will prove able to serve as inducers or organizers for subsequent phenomena. Third, simple universal mechanisms of steroid and enzyme action as now conceived will continue to be sought but will not be found. Rather the various hormones and enzymes will be seen doing different things in different tissues, and these tissue–substance reactions might, as indicated above, vary with time, age and condition. Particular responses of particular tissues, even in mosaic patterns, will be recognized as controlling factors in hormone efficacy. Significant advances in this particular area will come when either a new investigatory technique becomes available and perfected (X-ray diffraction analysis of molecular surfaces?) or a new type of mental synthesis is made of the already available data. It seems most likely that gene activity will be involved.
All parameters of human and animal sexual behavior and reproduction will get closer and more detailed scrutiny and all types of sexual practices will seem fit for study. Practices now publicly considered deviant or undesirable will be acceptable and some may even be advocated. Government will feel increasingly obligated rather than reluctant to probe these areas particularly in regard to the formulation of meaningful social and criminal legislation and the providing of optimum medical care.
With world conditions of war, poverty, slums, pollution, and other innumerable ills, the control of population growth will be of pivotal concern. This concern will ensure that funds for research at all levels will continue to proportionately increase. Sexual behavior, contraception, and family-planning methods will become amenable to both personal and social regulation. While the philosophers will ponder the appropriate values to accompany particular techniques, the public will demand access to them and society will encourage that some be used. Family planning will not always be left to individual families to plan and the state will increasingly be called upon to influence this now private matter.
Technical and scientific problems aside, the future is already upon us with enormous ethical and social problems with which we all will be involved by virtue of professional interests if not by personal concern. The resolutely accelerating glacial movement of population is fast becoming a torrential river, and individuals are more and more concerned with controlling, increasing or decreasing, the size of their families, herds, or pests. And while limiting production of some species, on the one hand, we may, on the other hand, find greater need for forestalling the extinction of other species (including our own) and increasing reproductive efficiency despite enormous changes in the micro and macro environment. Knowledge of every phase of the reproductive process will help in augmenting whatever control methods are sought and the magic nostrums may be on molecular and molar levels, with physiological and behavioral processes.
From a heritage of reproduction and sex as taboo and publicly ignored the future demands exposure and familiarity, knowledge and education. Even eugenic control is no longer an Orwellian radical myth and must be contemplated as a conservative fact. Against the urgency of problems so large some of the questions here discussed and presented will be called to do service. The prospects for the field of reproduction and sexual behavior are awesome.