established categories of sex.”
This point of view is gaining more and more adherents, as hard science comes to bear on questions of sex and gender. A 2005 paper produced by researchers at Goteberg University in Sweden presents evidence that an anomaly in the early sexual differentiation of various brain structures may be involved in transsexualism. The researchers found three common polymorphisms—genetic variations—that may influence the chances of transsexualism, providing support for the concept that transsexualism may be driven by genetics. In the language of molecular biology—“a long allele of the ERb gene may increase the susceptibility for transsexualism, and certain variants of genes coding for the AR, aromatase, and the ERb may partially contribute to the risk of male-to-female transsexualism if present in certain combinations.”
Each of these studies presents solid scientific data in support of the hypothesis that complex traits like sexual orientation and gender identity are biologically based and that anomalies in the sexual differentiation of the brain are entirely plausible. Other studies published over the past two years have similarly used the tools of molecular biology, genomics, and proteomics to explore possible mechanisms by which these might occur. This approach to sexual differentiation and development is not an isolated phenomenon; in fact it is part of the new systems biology. New tools and technologies like high-throughput genomics and bioinformatics are enabling scientists to analyze not just the actions of single genes, but of the vast arrays of genes and proteins that organize development.
The emerging picture is far more complex than previously suspected, and most likely involves genetic, epigenetic, and environmental factors. Citing the “complex and constant interaction” between the nervous system of the developing fetus and the intrauterine environment, as well as the interaction of the developing child with his or her family and community, child psychiatrist and urologist William Reiner says that we may never fully understand exactly how gender identity is established. On the other hand, recent studies have shown that the belief that one could alter a child’s gender identity afterbirth through the administration of hormones and surgery has been “an unmitigated disaster,” he says. Scientific opinion is gradually evolving, but some researchers are still clinging to the old point of view, citing insufficient data in support of the hypothesis that gender identity is established before birth. “But they are starting with the premise that the old way had some merit,” Reiner says. “I don’t agree with that. We never had the data to establish the validity of that hypothesis in the first place.”
As more data supports the view that biology plays a significant role in complex traits like sexual orientation and gender identity, the hypothesis that human sexual differentiation is vulnerable to the influence of endocrine- disrupting chemicals (EDCs) is also gaining support. In an article published in the journal
I spoke to Hood a few weeks before the article went to press and he told me that even though the EDC/transsexual correlation was mentioned only briefly, the article—which focuses on a range of potential effects —was likely to be controversial. Hood interviewed both Scott Kerlin of the DES Sons Network, and Christine Johnson, the engineer who has been the most vocal advocate for the EDC/trans hypothesis. Hood says that he found the data presented in Kerlin’s paper “surprising and enlightening,” adding that “it certainly points an arrow in a particular direction, which should be investigated.
“On its face, the concept that EDCs might cause transsexualism sounds a bit lunatic fringe,” he says. “But if you accept that there is or could be a physiological basis for gender identity, and if you believe that prenatal exposure to EDCs can affect neurological development, the concept begins to seem credible.” Whether it can ever be conclusively established is another matter, he says.
A study published by epidemiologist and biostatistician Shanna Swan in 2005 points to the kind of methodology that may ultimately convince skeptics. Swan found that anogenital distance—the distance between the rectum and the base of the penis—was shorter in baby boys whose mothers’ urine revealed elevated concentrations of phthal-ate metabolites. This evidence of “phthalate syndrome” previously observed in animal models provides compelling evidence that exposure to a class of chemicals used in a wide variety of consumer goods (soft plastics and cosmetics) is having a measurable effect on the reproductive anatomy of baby boys. Many are calling this a “landmark study” says Hood, pointing out that even Steven Safe, a noted critic of EDC fearmongering, has called it an important piece of work and a model for future epidemiological research on the human health effects ofEDCs.
It will certainly be more difficult to come up with that kind of overwhelmingly convincing evidence when it comes to psychological effects. Still, even in this murkier area, progress has been made. For example, in 2005, Scott Kerlin finally began to make some headway in his herculean efforts to bring the health issues of DES sons to the attention of researchers. After sharing his results with EDC researcher John McLachlan, Kerlin was invited to present his paper, “The Presence of Gender Dysphoria, Transsexualism, and Differentiation in Males Prenatally Exposed to Diethyl-stilbestrol: Initial Evidence from a 5-Year Study,” at the annuale. Hormone conference of endocrine disruption research in October.
This was Kerlin’s first experience at presenting his research to a scientific audience; I asked about the reaction to his presentation. “People were shocked,” he says. “Some audience members—including Shanna Swan— came up to me after the presentation and said, literally, ‘I’m shocked.’” Kerlin’s talk focused on the invisible harm of DES—things not easy to measure and difficult for people to grasp like gender dysphoria and major depressive disorders. “I basically said, I can’t prove it, but I also can’t discount the information that people have shared with me,’” he says. Contra his fears, the researchers in the audience “were not dismissive of my findings,” Kerlin says. Indeed, in his summary at the close of the conference, McLachlan referred to the work being done by Kerlin and some of the other presenters on the human health effects panel as “guerrilla epidemiology” and said that it was essential given the paucity of formal studies thus far.
Kerlin is pleased that he is finally able to call attention not only to the hot-button issue of gender variance, but also to broader psychological issues of DES sons. “I’ve documented more cases of major depressive disorders than any condition other than gender variance among members of the network,” he says, “but the whole psychiatric realm has been kept off the radar screen. All of the focus has been on measurable physical conditions. What is missing is long-term research on subtle effects, psychological health, and neurodevelopmental issues. My view is that males were disproportionately affected in ways that are relatively invisible, whereas the harm to females— particularly clear cell cancer—was impossible to ignore.”
In addition to McLachlan, the DES sons gained another powerful scientific advocate last year in Milton Diamond, the University of Hawaii professor best known for his revelation of the tragic outcome of the David Reimer case. When I spoke to Diamond in 2002, he was cautious in discussing the possible “gender-bending” effects of DES. Kerlin’s data has apparently convinced him that the topic is worth investigating; he nominated Kerlin’s paper for presentation at the International Behavioral Development Symposium held in Minot, North Dakota, in August 2005.
Kerlin was unable to attend so Dana Beyer, co-moderator of the DES Sons Network, presented the results to an audience that included most of the big guns of gender research, including many who still subscribe to the view that MTF transsexuals are self-hating homosexuals or “autogynephiliacs”—men sexually aroused by the thought of themselves as women. “While I received the usual criticisms from the usual suspects, the junior scientists were very appreciative of the data and were cognizant of its significance,” says Beyer. “The younger researchers seem to be accepting the increasing evidence that transsexu-alism is simply a form of intersex, where brain sex is incongruent with genital sex. It’s a slow process, but it’s picking up steam.”
Unsurprisingly, evidence that transsexualism may be associated with exposure to DES and environmental chemicals is welcomed by some transsexual and transgendered people, and viewed with alarm by others. Jay Sennett, a trans filmmaker and activist whom I met at my first True Spirit conference and who encouraged me to work on this book at a time when I was doubting my right to do so, expressed both points of view in a recent e-mail conversation. “I don’t want my people used in a fear campaign to reduce EDCs,” he says. On the other hand, given the widespread perception that transsexualism is a mental illness, data pointing to a correlation between transsexualism and EDCs may provide relief from the stigma. “Any proven biological component assuages the ick factor,” he says.
His major concern is how the media will “manipulate” such information. “Given the science phobia that is part
