We need to man up to avoid sterility

The concept of using ultrasound to knock out sperm was first proposed 40 years ago but abandoned.

What wasn't reported is that others have taken these results further in different species, including dogs and monkeys.

Slightly more worrying is the paper by an Italian team who achieved permanent sterilisation in dogs with two treatments. The long-term effects of such treatments remain unknown, so it is too soon to say whether this is a viable new method.

But while many papers reported the results with tongues in cheeks, they failed to grasp the importance of these studies. Contraception is critical to health, development and quality of life. Men have fewer options for controlling their fertility than women: vasectomy (perhaps inappropriate for men who still want children), withdrawal (usually a disaster), and condoms (unpopular among many committed monogamous couples). A safe, reliable, reversible, non-hormonal method for men would therefore meet a critical need.

One woman in seven dies in pregnancy or childbirth in Angola, Afghanistan, Malawi, Niger and Sierra Leone, versus one in 30,000 in England. In many parts of the world access to contraception can determine whether a woman lives past her twenties.

Ultrasound isn't the only male contraceptive being investigated; others involve heating methods based on the fact that the testes must be cooler than normal body temperature to maintain proper spermatogenesis. Sitting in a hot bath for 45 minutes every day for three weeks may lead to six months of sterility. Anything involving the testicles inevitably makes men squirm but it may be time for us to start putting ourselves on the line.

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