Another sexual revolution? Birth control pill for men on anvil

The invention of 'the pill' is credited with fuelling sexual liberation and the historic 'flower power' movement (make love, not war). But so far it was mostly the responsibility of women to make sure of popping their birth control pill to avoid unwanted pregnancies.

Now, scientists are close to developing a similar pill for men that could once again change the whole sexual paradigm. At least two projects are in the pipeline for a pill to temporarily choke male fertility.

One is H2-gamendazole that makes sperms go half-developed. Normally, premature sperm cells grow a tail and head in the testes, but H2-gamendazole keeps them from reaching this stage of development.

"If there's no sperm, the egg's not going to get fertilised," said Joseph Tash, a reproductive biologist at the University of Kansas Medical Centre. Tash has worked on the compound since 2001.

The other potential compound is JQ1 that can trick the body into forgetting how to make sperm. JQ1 was found blocking bromodomain proteins in cancer cells by Jay Bradner and his team at Harvard's Dana-Farber Cancer Institute. The uncontrolled division of the abnormal cells ceased due to it.

JQ1 also obstructed a testicle-specific bromodomain called BRDT, making the sex cells that would otherwise produce sperms draw a blank about their own behaviour.

Mice treated with JQ1 can copulate with abandon yet produce no offspring.

But it will be several years before the drug is available commercially. Researchers would have to find a version of the molecule that works on the testicle protein without any side effects.