The success of hormonal male contraception depends on the near complete suppression of spermatogenesis without producing any untoward effects on libido or other androgen-dependent functions or any other adverse events. The treatment with androgen alone has geen shown to be highly effective in Asian men but less effective in non-Asian men in clinical trials. To increase the efficacy of androgen alone treatment on spermatogenesis, combined regimens of a progestin and an androgen have shown promising results. The steady-state delivery of a progestin and an androgen by transdermal gel application would be a user-friendly delivery method as compared to injectable or implant approaches. Nestorone (NES) is a synthetic progestin that does not have any androgenic and estrogenic activity and is not expected to have some of the undesirable side effects of other drugs.