The real reason we don’t have a male pill
Times are a-changing, and many men want to take control of their fertility. So how long will they have to wait for a male pill?
For over half a century, women have been able to take control of their bodies to prevent pregnancies. But many men now want to share this responsibility with their partners. So how long will they be waiting for a male pill? WORDS: DR KAT ARNEY
More than 50 years ago, in 1960, the first female hormonal contraceptive pill, Enovid, was approved by the US Food and Drug Administration ( FDA), with the UK following in 1961. Just five years later, millions of pills were being popped around the world every day as women took control of their reproductive choices and health, creating a seismic change in society.
Today, women have a wide range of reliable, reversible options for controlling their fertility, including intrauterine devices ( IUDs), patches, jabs and implants. Men have just two: condoms, which have a 15 per cent failure rate under reallife conditions and are disliked by many couples, and vasectomy – cutting the tubes that shuttle sperm from the testes to the penis. And although vasectomy reversal is possible, it doesn’t always work. So why don’t we have a male pill?
The history of the male contraceptive pill has been a lot more up and down than the female pill. Its origins date back to the 1950s, when US biologist Gregory Pincus, one of the co-inventors of the female pill, found that doses of a synthetic version of the male sex hormone testosterone could switch off sperm production in the same way that the female hormones in the pill shut down ovulation. 2
2 “The physiology and science behind the male hormonal contraceptive pill is analogous to the female pill,” explains Prof Stephanie Page, an expert in male reproductive biology at the University of Washington in Seattle. “Giving men an external source of testosterone blocks their own production of the hormone in organs like the testes. They still have plenty of it in their blood, so it doesn’t affect the rest of their body, but developing sperm need 100 to 1,000 times as much testosterone for their final maturation and there just isn’t enough in the testes to enable them to finish developing.”
SPERM STOPPER
At the University of Minnesota, chemistry professor Dr Gunda Georg is taking an alternative approach. She and her colleagues are investigating a chemical called ouabain – a potent toxin produced by plants, which was originally used by east African tribes to coat the tips of their hunting arrows. It exerts its effects by blocking molecules called sodium potassium ion transporters, which normally shuttle salts in and out of cells. Curiously, one particular component – the alpha 4 subunit – is only found in transporters in sperm cells, and nowhere else in the body.
“When we removed the gene encoding the alpha 4 subunit in male mice, we found that they were quite normal in all respects except that they were infertile,” Georg says. “The animals even made normal sperm, but they couldn’t swim up the fallopian tube to get to the egg and they couldn’t do the final wriggling movement that leads to fertilisation. This suggested that if we could develop a drug that selectively blocks alpha 4, then this would be a promising approach for male contraception.”
In search of ideas, Georg and her team hit the textbooks, looking for ways to modify the chemical structure of ouabain so it would only hit alpha 4 and nothing else. Then once they’d tweaked the molecule, they tested it in rats to see if it would work. Amazingly, they hit the jackpot first time. 2
“The science behind the male pill is analogous to the female pill”