The use of ultrasound to induce temporary male infertility is being explored with funding from the Gates Foundation.

The new treatment offers the prospect of men being able to gain six months of contraception through 15 minutes of painless ultrasound.

The effect of ultrasound on sperm production has been known since the 1970s. Dr. Mostafa Fahim at the University of Missouri-Columbia discovered that 10-15 minutes of ultrasound waves to the testes could induce temporary sterility in various mammals. Multiple applications resulted in permanent sterilisation.

Widely dismissed during his lifetime, Dr. Fahim's discovery formed the basis of a nonsurgical sterilisation treatment for dogs commercialised in the USA in 2002. Funding for development of this therapy in humans has been impeded by widespread reliance on female contraception. However, the growing incidence of vasectomy has demonstrated a shift in attitudes.

In 2007, the Parsemus Foundation funded a proof of concept study at the University of North Carolina that established an effective dose level and treatment protocol. The UNC team has now gained funding from the Gates Foundation Grand Challenges Explorations.

Gary Gamerman, a regulatory consultant for contraception programmes, said: "There are a lot of questions to be answered still about ultrasound. There's more human data on some of the new methods, like RISUG for men or the new IUDs for women. But Gates is trying to do something new here - give new ideas a chance."

Elaine Lissner, director of the non-profit Male Contraception Information Project, agreed: "With the Grand Challenges Explorations approach, they're taking a venture capital-style approach to funding new techniques. Not all the ideas will make it to market - but if you never try, you'll never know. This day has been a long time coming."