Genes, Not Genitalia, Are Key To Gender

Genetics, not just anatomy or hormones, strongly influence gender, according to research that raises questions about sex-assignment surgeries for 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," genetics and sexual medicine expert Dr. Eric Vilain, said in a prepared statement. Vilain was a member of a special panel convened Feb. 18 at the American Association for the Advancement of Science annual meeting in Washington, D.C.