The Riddle of Gender - Deborah Rudacille [168]
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 Environmental Health Perspectives in October 2005, science writer Ernie Hood reports on the debate raging among scientists who are convinced that EDCs present a hazard to human health and skeptics who insist that EDCs have not been proven harmful to humans. For the first time a peer-reviewed scientific journal—EHP is the journal of the U. S. National Institute of Environmental Health Sciences—raises the issues of whether prenatal EDC exposures may be a causative factor in transsexualism/ transgenderism.
I spoke to Hood a few weeks before the article went to press and he told me that even though the