Birth control pills for men have been researched for years – with little success, because of hormonal side effects. The newest pill works as an ‘anti-vitamin’ and leaves the libido untouched.

Temporarily shutting down fertility is medically somewhat more challenging in men than in women. Instead of ovulating just once per month, men produce millions of sperm cells each day – none of which should slip through the net. Hormonal contraception therefore only works with relatively high doses – which may be associated with side effects such as decreased libido.

That’s why a group of American scientists decided to look for an alternative route to inhibit spermatogenesis. And in mice at least they have found one. Their research has just been published in Endocrinology.

Artificial vitamin deficiency

Earlier research has shown that the production of sperm cells can stop in people and animals with severe vitamin A deficiencies. Such shortages are in the western world uncommon [we suffer more health problems due to vitamin A overdosage – especially in people taking supplements] but also undesirable, as of course the vitamin is essential to various body functions, and not just night vision.

But in the testes the route goes through a specific receptor, the pan-retinoic acid receptor, that may not be of equal importance elsewhere in the body.

Retinoic antagonist

The new pill therefore contains an antagonist, which creative biochemists gave the name BMS-189453, but that may be very effective in saving others the concern of thinking of more charming names for daughters or sons – as it effectively stops spermatogenesis in relatively small doses, the researchers find.

Health risks were not found in the short run – so multi-year trials are now being prepared. The mice returned to full reproductive capacity after the drug administration was ceased.

Practical demography management

Although we feel this new pill may still meet tough cultural and psychological resistance – and we are not completely convinced consequently blocking a vitamin receptor could be as harmless as stated, there may still be couples for whom this is the kind of good news they have been waiting for.

Primary concern when it comes to birth control and contraceptives though should perhaps be to return to the basics. And this new pill will definitely not have a changing effect in places that the estrogen and progesterone pills – or even the condom somehow failed to reach.

© Rolf Schuttenhelm | www.bitsofscience.org