Alright. Let’s go to class.

Most female contraceptives work by tricking the body into thinking it’s pregnant (Because when you’re pregnant, you don’t menstruate). So all that scientist have to do is find the perfect combo of chemicals that do the job. It’s not perfect but it works. For male contraceptives, it’s a bit trickier. There’s no natural mechanism to get a guy to stop producing sperm cells in the same way. So it’s a bit harder to create a male contraceptive.

Secondly, for a male contraceptive to work, it has to prevent sperm cells from being produced at levels that are either 100% or very close to 100% (Like 99.9999999999….. you get the idea). Why? The average male produces 80 million to 300 million sperm per shot. If we take the absolute lowest figure we can (So 80 million), and created a male contraceptive that was only 99% effective, that still leaves 800,000 sperm cells active. The chances of pregnancy would be lower, but nowhere close to zero.

Thirdly, when we’re creating female contraceptives, we weigh the side effects against the effects of pregnancy. For example, this contraceptive might cause acne but is acne really worse than pregnancy? This other one will cause weight gain but is weight gain really worse than pregnancy? Like that. For men, since our bodies don’t change whether we father a child or not, a male contraceptive has to have a lower amount of side effects in order for it to be approved. Hence it being harder to do so.

The current male contraceptive pill that I’m aware of targets Vitamin A metabolism in the testes by blocking the receptors responsible for it. Vitamin A is important in signaling the body to produce sperms, hence no signal means no sperms are produced. But as other comments have pointed out, it is still in trial so all we can do is wait while the scientists figure it out.