From sex and gender to hormones, behavior and culture

According to legend, Hermaphroditos, the son of Hermes and Aphrodite, was swimming in a pool when Salmacis, an enamored nymph, embraced him with both arms and legs, praying that they would never be separated, after which they merged into a single body. A brilliant interdisciplinary perspective on sexuality is given in Fausto-Sterling's book, Sexing the Body. Artfully entwining biological and social sciences, the author accompanies the reader on journeys from anatomy to genes and hormones to behaviors, at the same time providing an invaluable reference for general audiences and a thought-stimulating resource for academic discussions.Sexing the Body begins by examining intersexuality across cultures, legal systems and religions; highlighting the complex challenges a two-sex model can engender, it brings forward interesting examples. These include a young male soldier giving birth to a baby girl in 1601, and a ‘more female than male’ Connecticut resident's voting rights being at stake in 1843. When Maria Patino, Spain's 1988 female Olympic athlete was examined and a Y chromosome was found extensive controversies ensued. An Australian court dissolved the marriage of a person born with a right ovary and a left testicle, because they ‘could be neither male nor female’, and a British court has annulled a woman's marriage because she was born without a vagina. The author of Sexing the Body argues that although the current definitions of homo- and heterosexuality are based on a two-sex model, human beings are too complex to fit into a binary definition of sex – many bodies being a mixture of traits with ‘male’ and ‘female’ representing just the extremes of a continuum. As she points out, even our language only allows two possibilities, ‘he’ or ‘she’, without leaving room for individuals who are neither clearly male nor female. Fausto-Sterling argues that whether we label someone a woman or a man should not be solely defined by biological sciences, but it should instead be a social decision. The author shows how modern surgery, rooted in the assumption that only two sexes should exist, helps perpetuate the two-sex system. She reflects on the great variability of intersex surgical practices and on the absence of consistent standards to evaluate long-term psychological well-being: for instance she highlights that in many clitoral surgery cases only cosmetic criteria are considered whereas sexual function goes understudied.Although surgery for intersex babies is a subject of debate, Fausto-Sterling's argument that ‘we protest the practices of genital mutilation in other cultures, but tolerate them at home’ can be challenged at several levels. Countless aspects distinguish intersex surgery from genital mutilation, and with genital mutilation being a horrifying and unsanitary procedure performed for purposes other than medical, the two cannot even be compared with each other. Revisiting her previous proposal that a five-sex system instead of the current dual system would better incorporate hermaphrodites and pseudo-hermaphrodites, the author acknowledges that she no longer advocates the use of these discrete categories but reminds us that it is the social gender that we readily see and should use, instead of the physical gender.The chapter describing the lengthy struggle by investigators to understand the effects of estrogen and testosterone is particularly enlightening. The author claims that apart from their sexual effects, these hormones have an impact on numerous other organs and therefore could be considered growth hormones. To underscore how their sexual effects have received attention but consideration of their many non-sexual effects has fallen into oblivion, she points out that in defining and measuring estrogen, only its effect on the estrus cycle was considered. Emphasis is placed on the adequacy and shortcomings of rodent experiments in constructing theories of sexuality, and the author elaborates on models that have furthered our understanding of the relationship between masculinity and femininity. One interesting argument is that the control of hormone synthesis differs between primates and other species and therefore studies on non-primate sexual behavior divulge little about human sexuality.Fausto-Sterling concludes the book with a brilliant analogy: although visible and beautiful, individual Russian nesting dolls are hollow, and only their assembly and disassembly offer an ideal comprehension. Similarly, human sexuality is best visualized from an interdisciplinary perspective, by integrating biological and social sciences. The discussions focusing on intersexuality and on the history, chemistry and effects of sex hormones render Sexing the Body an interesting read for endocrinologists. Furthermore, the section on the corpus callosum, revisiting the vast literature in the field, provides important lessons on research methodology and will greatly benefit researchers.