A small study of a male birth control pill achieved the elusive goal of reducing sperm counts to zero in all participants, a Scottish researcher said Wednesday. David Kinniburgh of the University of Edinburgh led a team that tested the contraceptive in 30 Scottish and 36 Chinese men. Kinniburgh spoke at a news conference after presenting his findings at an international obstetrics and gynecology conference here.
Progestins are synthetic steroids.
To test the effectiveness of different doses, half the men received more than the others. Individually, progestins and testosterone have been shown to suppress sperm production. Together, they appear to be even more effective. Since testosterone taken orally is immediately broken down by the liver, it can't yet be prescribed in pill form. All of the men on the bigger desogestrel dose saw their sperm counts plummet to zero, as did more than two-thirds of those on the smaller dose.