Jacques Balthazart – författare

In this fascinating book, Jacques Balthazart presents a simple description of the biological mechanisms that are involved in the determination of sexual orientation in animals and also presumably in humans. Using scientific studies published over the last few decades, he argues that sexual orientation, both homosexual and heterosexual, is under the control of embryonic endocrine and genetic phenomena in which there is little room for individual choice. The author begins with animal studies of the hormonal and neural mechanisms that control the so-called instinctive behaviors and analyzes how this animal work may potentially apply to humans. The book does not focus exclusively on homosexuality, however. Instead, the book acts as a broader guide to the biological basis of sexual orientation, and also discusses important gender differences that may influence sexual orientation. While firmly grounded in the scientific literature, this text is developed for a broader audience and will be of interest to psychologists, researchers, students, and anyone interested in the biological factors that determine our sexuality.

It is well known that the class of steroid hormones known as estrogens have powerful effects on organs related to reproduction such as the uterus and the breast. What is less well known is that estrogens also profoundly modulate brain function and behavior. Estrogens, such as estradiol, can occur in brain as the result of ovarian secretion of the hormone into the blood that then finds its way to the brain. In male vertebrates, the testes secrete androgens, such as testosterone, into the blood and this class of steroid hormones can be converted into estrogens in the brain via the action of the enzyme aromatase which is expressed in the male brain in many species. Finally estradiol can be synthesized de novo from cholesterol as it has been shown in a variety of species that all the enzymes required to synthesize estrogens are expressed in the brain. This book collects chapters by experts in the field that considers, how estradiol is synthesized in the brain and what its effects are on a variety of behaviors. Special attention is paid to the enzyme aromatase that is distributed in discrete regions of the brain and is highly regulated in a sex specific and seasonal specific manner. Recently it has become clear that estrogens can act in the brain at two very different time scales, one is rather long lasting (days to weeks) and involves the modulation of gene transcription by the hormone-receptor complex. A second mode of action is much quicker and involves the action of estrogens on cell membranes that can result in effects on second messenger systems and ultimately behavior within minutes. Thus this book highlights novel views of estrogen action that are still under-appreciated namely that estrogens have significant effects on the male brain and that they can act on two very different times scales. This volume will be of interest to both basic researchers and clinicians interested in the action of estrogens.

Research in biology and all basic sciences has undergone profound transformations in recent decades. We have seen the development of extremely sophisticated techniques, allowing us to study, in an objective manner, questions that were still considered science fiction at the end of the 20th century. All of this has allowed us to develop an in-depth knowledge of vast subjects, such as the biology of the brain, for example. Fifty Years of Evolution in Biological Research presents a panorama of these different technical advances. However, at the same time, there has been an increase in the number of constraints on researchers, a monetization of research and a correlative pressure to continually publish in more prestigious journals. This has resulted in a certain degradation of the quality of research activity. This book analyzes this evolution and proposes solutions.

Research in biology and all basic sciences has undergone profound transformations in recent decades. We have seen the development of extremely sophisticated techniques, allowing us to study, in an objective manner, questions that were still considered science fiction at the end of the 20th century. All of this has allowed us to develop an in-depth knowledge of vast subjects, such as the biology of the brain, for example. Fifty Years of Evolution in Biological Research presents a panorama of these different technical advances. However, at the same time, there has been an increase in the number of constraints on researchers, a monetization of research and a correlative pressure to continually publish in more prestigious journals. This has resulted in a certain degradation of the quality of research activity. This book analyzes this evolution and proposes solutions.

Research in biology and all basic sciences has undergone profound transformations in recent decades. We have seen the development of extremely sophisticated techniques, allowing us to study, in an objective manner, questions that were still considered science fiction at the end of the 20th century. All of this has allowed us to develop an in-depth knowledge of vast subjects, such as the biology of the brain, for example. Fifty Years of Evolution in Biological Research presents a panorama of these different technical advances. However, at the same time, there has been an increase in the number of constraints on researchers, a monetization of research and a correlative pressure to continually publish in more prestigious journals. This has resulted in a certain degradation of the quality of research activity. This book analyzes this evolution and proposes solutions.

L''homosexualité au cœur des interrogations scientifiques.Il est couramment admis que l’orientation hétéro- ou homosexuelle d’un individu est essentiellement, voire exclusivement, le résultat d’apprentissages et d’interactions sociales qui se déroulent dans la petite enfance. Sous l’influence de théories psychanalytiques freudiennes et postfreudiennes, un rôle tout particulier a été attribué aux interactions du petit enfant avec ses parents dans le développement de l’homosexualité. Cette dernière serait alors le résultat d’un blocage du développement de la libido à un stade immature. Ces opinions très répandues ne sont cependant pas soutenues par des études quantitatives contrôlées et ignorent une littérature scientifique abondante qui suggère fortement, voire démontre que l’homosexualité dépend largement de déterminants biologiques prénataux.Vu la complexité de la personne humaine, ceci n’exclut pas qu’il puisse exister des homosexuels pour qui cette orientation constitue un choix de vie délibéré, éventuellement influencé par des expériences antérieures. Cependant, une large proportion des homosexuels naissent avec cette orientation sexuelle qui se révèle à eux de façon progressive au cours du développement et n’est souvent acceptée qu’au prix d’une souffrance psychologique importante. Une compréhension de ces mécanismes biologiques devrait conduire à une acceptation plus large de l’homosexualité dans la population et réduire la souffrance des personnes concernées. Ce livre a pour but de rendre accessible à un large public la littérature scientifique sur les bases biologiques de l’orientation sexuelle et donc de corriger les conceptions erronées très répandues au sujet des origines de l’homosexualité.Cet ouvrage de référence apporte un éclairage sur l''homosexualité en reprenant les théories sociales, psychologiques et biologiques à son sujet.CE QU''EN PENSE LA CRITIQUE En homme de science, l’auteur s’adresse au lecteur dans un langage compréhensible. (...) Un hymne à l’acceptation. Un outil pour aider les homosexuels à s’assumer. - Eos, n°26Il va de soi que ce livre bat totalement en brèche les propos pseudo-scientifiques du futur primat de Belgique qui appuye sa vision de l''homosexualité, une anormalité dans le développement de la personne, sur la théorie freudienne. Sa parution vient donc bien à point nommé ! - Gay KosmopolÀ PROPOS DE L''AUTEUR Jacques Balthazart dirige le Groupe de Recherches en Neuroendocrinologie du Comportement (GIGA-Neurosciences) et est Chargé de cours à l’Université de Liège (Belgique).

Understanding the brain mechanisms which underlie behavior is one of the most challenging tasks of modern biology. The study of these mechanisms can be approached using a variety of biological systems as models, depending essentially on the type of question being asked and the technical approach which is considered. In vertebrates, the study of brain neurochemistry in relation to behavior e,xpression has made tremendous progress during the last two decades. In particular, much at­ tention has been devoted to the effect of steroid hormones on brain structure and activity in connection with social and mainly reproductive behavior. This book exemplifies some of the major trends in the field. I did not attempt to cover exhaustively all the work that has been done in this area but rather to present a series of selected reviews on the molec­ ular and cellular brain mechanisms most directly related to social behavior. This selection obviously reflects my own interests but also, I believe, highlights those areas of research in which important progress has been made in recent years. A number of brain biochemical or cellular mechanisms which could be related to behavior, but have not been formally demonstrated to be so, are consequently ignored. The focus here is on social behavior and thus steroid-dependent processes are covered in priority. This choice of course leads us to ignore major trends in brain and behavior research but this is, I hope, clearly reflected in the title of the volume.