For almost 50 years, researchers have searched for effective, well-tolerated, reversible male hormonal contraceptives (MHCs). Vasectomy aside, current male contraceptives are not especially reliable: condoms and withdrawal have unintended pregnancy rates of 15-20% and 25-30% a year respectively.1 So, a ‘Pill for men’ could prove popular. Surveys suggest that more than 50% of men might try a MHC. Just
2% of women would not trust their partner to use a hormonal contraceptive.2 They might not have much longer to wait. Recent advances raise the prospect of reversible MHCs ‘within a decade’. Nevertheless, ‘major challenges remain’.3
Healthy sperm production
Each millilitre of ejaculate from a healthy man contains between 15 million and 150 million sperm.1 A man needs to produce between 13 million and 15 million sperm per ml for normal fertility.4 To attain these concentrations, the testes continually produce sperm, controlled by a hormonal cascade.3,5
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