Oral male contraceptive composition

An orally active male animal contraceptive composition for substantially inhibiting sperm production without substantially affecting the activity of secondary sex organs during administration periods, which comprises:

• a biologically acceptable and orally active form of gossypol in a dosage of 3-30 milligrams per kilogram body weight per day;
• and
• a biologically acceptable and orally active replacement androgen selected from the group consisting of fluoxymesterone and medroxyprogesterone in a dosage of 1 to 5 milligrams per kilogram per day.

A method of substantially inhibiting sperm production in male animals without substantially inhibiting the activity of secondary sex organs during administration periods, which comprises:

• orally administrating a biologically acceptable binaphthalamine structure compound selected from gossypol and gossypol derivatives at a dosage whereby said sperm production is substantially inhibited to below the azoospermia level;
• and
• orally administering a biologically acceptable orally active replacement androgen at a dosage whereby said activity of secondary sex organs is substantially unaffected by said gossypol and gossypol derivatives.