A SEVEN-year-old girl with a Y chromosome is providing new clues about a possible “master switch” of maleness.
Other children who have the male sex chromosome but do not appear to be boys have been found to have gene mutations that temper the Y chromosome’s effects. They generally have indeterminate gender characteristics such as ambiguous gonads, shrivelled testes or other developmental abnormalities.
This child has the physical attributes of a girl, however, with a normal vagina, cervix and ovaries, according to a team led by Anna Biason-Lauber of , Switzerland (The American Journal of Human Genetics,
