A way to keep sperm at bay?

When it comes to new male contraceptives, the ideas might make some cringe: Injections. Plugs. Implants.

But a UNC-Chapel Hill researcher is hoping ultrasound technology - the same energy used to treat sore muscles - will temporarily shut down the sperm factory, providing painless and inexpensive birth control.

Ultrasound has been suggested as a male contraceptive since the 1970s, but James Tsuruta, a reproductive health biologist at UNC-CH, won a $100,000 grant this week from the Bill & Melinda Gates Foundation to move thescience forward.

"One 10- or 15-minute treatment might last six months," Tsuruta said. "It's really quite a dramatic effect."

The current options for male contraceptive methods amount to a short list: Vasectomy, condoms and withdrawal.

Having a new choice, particularly one that is easy to use and has some lasting effect, would give men the same kind of control over their reproductive destinies that the pill granted women 50 years ago.

Global benefits

And in developing countries, reducing unwanted or unplanned births would have significant social and economic benefits. That was the Gates Foundation's interest in Tsuruta's proposal.

Tsuruta said the ultrasound machines are relatively inexpensive - about $1,300 - and fairly easy to use.

A wand delivers high frequency sound waves from a portable power source, and an enterprising technician could make the rounds in remote villages, performing the sterility treatments every six months.

Elaine Lissner, director of the California-based advocacy group Male Contraception Information Project, said the zeal to find new male contraceptives had been lacking for years.

One route for sperm

"You see a lot people saying that with women, there's only one egg, and with men there are thousands and millions of sperm," Lissner said. "But that's a bit of a fallacy. The sperm all travel through one tube, and it's all produced in one place. You can catch them in the tube, or affect them where they're produced. It just takes thinking a little more creatively."

The ideas for men have been plentiful, if disconcerting. Heat inhibits sperm production, leading to the suggestion of lengthy sitz baths, or a wearable, battery-powered pouch. There are notions of implants to dam the flow of sperm; injections of chemotherapy into the testes; a Chinese herb that keeps sperm from swimming effectively.

Notions abound

Interest in developing new methods has recently increased, Lissner said, with funding from federal grants, the Gates Foundation and the Parsemus Foundation, which focuses on research often neglected by larger agencies.

Tsuruta's project was initially funded through Parsemus, and the Gates money will enable him to test the ultrasound technology on rats. It basically works by delivering a pulse of energy to the testes, which disrupts the production of sperm. Tsuruta said the exact mechanism is unclear, and it may be identified through his research.

Not there yet

"Maybe the ultrasound causes an imbalance in sodium and potassium in the testes, and that has to be just right" for sperm production, Tsuruta said.

Lissner said the ultrasound approach is among the most promising in the current crop of ideas.

"There is a lot still to be worked out," she said, "but we'll never know until we try."