WASHINGTON, DC--Gender, often said to depend solely upon anatomy or hormones, may depend also on hard-wired genetics, according to new research that could help doctors and lawyers better understand the one in 4,000 babies born with both male and female traits.
"The biology of gender is far more complicated than XX or XY chromosomes and may rely more on the brain's very early development than we ever imagined," researcher Eric Vilain, M.D., reported today at the American Association for the Advancement of Science (AAAS) Annual Meeting in Washington, D.C.
"Surgical sex assignment of newborns with no capacity to consent should never be performed for cosmetic reasons, in my opinion," said Vilain, an associate professor of human genetics who also serves as a chief of medical genetics and director of research in urology and sexual medicine within the David Geffen School of Medicine at the University of California, Los Angeles. "We simply don't know enough yet about gender to be making surgical or legal assumptions."
Another AAAS speaker, William G. Reiner, M.D., agreed. "The most important sex organ is the brain," said Reiner, a psychiatrist and associate professor in the Department of Urology, Oklahoma University Health Science Center. "We have to let these children tell us their gender at the appropriate time."
An estimated 1 in 4,000 to 1 in 5,000 babies may be classified as "gender ambiguous" because intersex conditions affecting their genitalia, reproductive systems or sex chromosomes make an immediate assessment impossible, Reiner explained.
Yet, many laws -- including U.S. marriage laws -- assume that everyone is clearly male or female, a concept known in legal circles as sexual dimorphism, or binary law, legal expert Susan Becker of the Cleveland State University explained at the AAAS Meeting. At the same time, children with ambiguous genitalia continue to underg