For years, scientists have attempted to create a male version of the contraceptive pill.
They haven't quite managed it yet, but a new discovery by a group of researchers at Osaka University in Japan has given them a big push in the right direction.
By carrying out tests in mice, they managed to block a key sperm protein called PPP3CC/PPP3R2, which is responsible for pushing sperm through the egg's tough outer membrane.
This, they discovered, made the rodents temporarily infertile, with reproductive ability returning a week after treatment ended. Details of the study are published in the journal Science.
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While they don't know for certain that the same result would arise in human males, the researchers believe there's a strong chance it would create reversible, fast-acting infertility in a similar manner.
“Considering these results in mice, sperm calcineurin may be a target for reversible and rapidly acting human male contraceptives,” they write.
This would potentially be a huge breakthrough for the pharmaceutical industry, which is currently flooded with female versions of “the pill” but has nothing for men.
However, if a male contraceptive pill is developed within the next few years, it will face a potential stumbling block – it's risky for drugs companies to take on new medicines without having evidence that they'll perform well, and the fact that a male pill has never been created before means it's hard to tell how it will go down with men across the world.
“There's no other product like this on the market,” Mike Mitchell, healthcare analyst at Panmure Gordon, told City A.M.“It's challenging to predict whether it would be commercially successful because there's no existing market for it.”
He said adoption of the product would depend on perceived consumer demand, and that some men might be reluctant to use it due to a lack of cultural history of men using this kind of birth control.
On top of this uncertainty, there is the practical difficulty of creating a pill that affects male fertility:
It seems to be much easier to create a contraceptive pill for women than for men because of female monthly cycles. These provide an easy access point for interruption, and the fact that men do not have this makes them a much more complicated case.However, the creation of a male pill, if it is achieved, would provide an interesting platform for other hormonal treatment applications.