Sex Reversal: Genetic Women Become Adult Men

Female-to-Male Sex Reversal Found in 3 U.K. Family Members

By Daniel J. DeNoon
WebMD Health News
Reviewed by Laura J. Martin, MD

Jan. 5, 2011 -- Two adult brothers and a paternal uncle in the U.K. all appear to be normal males -- but genetically are women with two X chromosomes.

Both brothers are married to women, and they and their uncle have the sexual anatomy, behavior, growth, and skeletal development of males. All have normal health and intelligence.

However, all three are infertile and unable to produce sperm. When the brothers responded to testosterone replacement with pain, their testes were removed and replaced with cosmetic prostheses.

Genetic tests showed that both they and their uncle lacked a Y chromosome. Instead they had the two X chromosomes characteristic of women (normal men have one X and one Y chromosome).

(More here.)