The reality is that developing male birth control is a medically tricky proposition. However, the responsibility of preventing pregnancy has historically fallen on women's shoulders, andthis means women have also borne the burden whenever access to birth control has become politicized and restricted. Yes, condoms work in the short-term. Yes, vasectomies can take care of unwanted fertility, too. But it would be pretty nice if there were a reversible male contraceptive — so why exactly don't we have one yet? It turns out that the answer is about more than just scientific progress. Here's what's really going on, according to the experts.

How would reversible male birth control actually work?

First, a little anatomy refresher: Female hormonal contraception, including the pill, essentially works by tricking your ovaries into thinking you're already pregnant.

"During pregnancy, female hormones increase dramatically and, among other things, they signal the ovary to stop producing eggs," David Sokal, board chair of the nonprofit Male Contraception Initiative (MCI), tells Allure. "The development of the pill in the 1950s took advantage of this natural process." While the amount of hormones in the pill is lower than the amount that would be in your body if you were actually pregnant, it's still high enough to signal your ovaries to pump the brakes and not release an egg.

A male birth control pill, meanwhile, "would essentially be something that a man would take that would suppress sperm production," Los-Angeles-based urologist and sexual medicine specialist Joshua Gonzalez tells Allure.

As Sokal points out, though, men don't have sperm production cycles: The testes just continuously produce sperm. Male birth control researchers are looking for a way to stop sperm production altogether using progestin, which is used in hormonal birth control for women. Progestin is the synthetic version of progesterone, a sex hormone that is produced mainly in the ovaries. The progestin route is promising, but not without its side effects. Mood changes caused by hormonal birth control might be more severe in men than they are in women, Sokal says.

Researchers are also exploring non-hormonal forms of male birth control. New research points to the possibility of using an ancient, plant-derived poison called ouabain, per a study published last month in the Journal of Medicinal Chemistry. It's possible that a non-toxic version of this poison could impact human sperm's ability to swim to an egg. Don't hold your breath, though: The first human clinical trials of this option are years away, researchers say.

You might also have seen headlines about Vasalgel, a scrotal injection that could function as male birth control. The procedure has only been tested in animals, but it works by physically blocking the tube that sperm swim through (the vas deferens) with a polymer gel. To reverse the sperm-blocking effect, a second injection could be used to flush the polymer out. Researchers are still conducting pre-clinical testing on Vasalgel, and according to Vasalgel's website, the goal is to begin conducting human clinical trials this year. "Again, this is also years away from becoming a reality [available to consumers]," says Brahmbhatt.

Why is developing reversible male birth control so hard?

Some of the difficulty is simply that the science just isn't there yet. So far, research has focused on the problem of prolific sperm by trying to shut down the production entirely in a way that's more easily reversible than a vasectomy. (While vasectomies can be reversed, they're considered permanent birth control because reversal isn't always successful. Only people who are not planning on having any further children are recommended to get vasectomies.)

"All compounds [that shut down sperm production] had some fatal flaw, such as severe side effects or not being reversible in all men," Sokal says. "In recent years, more researchers are instead beginning to focus on affecting sperm function rather than halting sperm production" — for example, by altering sperm's ability to fertilize an egg or hamstringing their ability to swim (such as with the research on ouabain).

The fact remains, however, that there are just so many damn sperms to worry about. "The difficulty with male birth control has always been the difficulty that comes with having to control a million plus sperm into not advancing into the ejaculate, whereas in women you have to focus on one egg per cycle," Jamin Brahmbhatt, a urologist in Clermont, Florida, tells Allure.

But beyond the physical challenges, cultural and political realities have also made developing a male birth control pill really tricky. "I don't think there's really been an impetus to develop it because the female pill has been around for so long. I think there's an idea that females should be responsible for whether or not they get pregnant," Gonzalez says. "There's a lot of sociocultural political variables that go into it." It should come as no surprise, then, that research dollars are by and large devoted to improving the efficacy of hormonal birth control for women. There are significantly fewer resources available for researchers working on methods for men.

All the scientific challenges combined with the sociocultural climate around birth control have created a kind of perfect storm preventing a male pill from hitting the market. As long as effective female birth control has been widely available, researchers simply haven't been able to prioritize developing a male version of the pill, Sokal says.

What kind of hope should we have for long-acting, reversible male BC?

Despite the challenges, there is a growing number of researchers tackling the challenge of equalizing contraception. Sokal points to the Male Contraceptive Development Program, which was recently established under the National Institutes of Health, as a promising example of the increasing support for the field.

Meanwhile, the Male Contraception Initiative is applying nonprofit dollars to the problem. In 2017, the organization awarded a $500,000 research grant to Vibliome Theraputics, Inc. to help develop a non-hormonal male birth control pill that would work by manipulating an enzyme essential for male fertility. "In 2018, we are planning to award even more funding to researchers to speed the process of bringing a new male contraceptive to market in this century," Sokal says.

Unfortunately, even the most promising research won't be showing up in pharmacy aisles anytime soon. "The truth still remains that we have great female birth control but are far, far away from something just as good in reversible form for men," Brahmbhatt says. (Of course, many women might contest this blanket assessment of the female contraceptive options out there, but there are at least more of them.) Sokal estimates it will be at least another 10 to 20 years before we see a safe, effective, and reversible birth control option for men that are comparable to the pill.

So what should men do while they wait for their own pill?

There are, of course, other methods of male birth control. Condoms are chief among them, even though they are only 85 percent effective in real life, per Planned Parenthood. Of course, condoms have the significant added benefit of helping protect against STIs, which birth control medication doesn't do. Vasectomies, meanwhile, offer a more permanent solution for people who are convinced they don't want kids (or don't want more kids than they already have).

Even if researchers do develop a male version of the pill, will guys actually use it?

According to research from MCI, the answer is yes. Sokal says the group's market research indicates that most men do want equity in contraception, meaning a reversible form of contraception for men could be a real game-changer for the birth control landscape.

Brahmbatt says he too has faith that men will want to take charge of birth control in their relationships if given the chance. "They are just waiting for the right medication to come out," Brahmbhatt says. "Until then, they should stick with what's tried and proven to be effective to avoid babies and STDs: condoms."