The XY female in sport: the controversy continues.

The summer and winter Olympic Games have been accompanied by much press coverage of the controversy and confusion over sex tests for sportswomen. Much of this has centred on the eligibility of subjects with androgen insensitivity to compete in women's events. The purpose of this paper is to review the process of sex differentiation and its abnormalities, highlighting those conditions in which biologically active testosterone is secreted which might confer an advantage in women's sporting events.