字幕表 動画を再生する 英語字幕をプリント Let's talk about sex. I know that's the last thing most of you wanted to hear me say, but I have big science-related news about it! Right now clinical trials are underway for a new form of birth-control for men. Currently if you're a man and you want to be the responsible one while doinking, there's really only two options - a vasectomy, which is not convenient or always reversible; or a condom, which is convenient, cheap, and effective at stopping both pregnancies and STDs when used correctly. But some men don't like the way a condom affects the sensation of sex and would rather do without it. Or so I've heard. So the two methods of male birth control rely on physical barriers to stop sperm from reaching an egg. By contrast, there are a lot of female birth control options, and most of them use hormones to prevent an egg from being around in the first place. So what's stopping men from using some kind of hormonal birth control too? Well in theory, nothing really, and male hormonal birth control has been tested before, though so far none have been successful. This new clinical trial is aiming giving it another shot, testing the drug on men in 7 countries around the world. The new drug uses two hormones. One is progestin, a synthetic form of the steroid/hormone progesterone that women's bodies use to regulate ovulation and pregnancies. The purpose of the progestin in the experimental new male birth control is to lower sperm count. But to prevent the progestin from negatively impacting the men's sex drive or causing other changes like increased acne or weight gain, the second hormone present is testosterone. That may sound counterproductive since testosterone plays a role in sperm production, but actually when a man's body gets testosterone from an outside source, the testes stop producing it and sperm count drops as well. Perhaps best of all is the form this birth control comes in. It's a gel that's intended to be rubbed on the arms and shoulders, so guys there's no excuse not to use it because it doesn't feel good. Heck you play your cards right and you can literally get a massage out of it. A rub-on gel is a lot kinder of a delivery system than say a pill, or a vaginal ring, or an IUD, or an implant, or a shot, or basically any method women currently have for hormonal birth control. But it's not something that a man can slap on, give himself a quick rub, and get right to the business of no-baby-making. Men make 1,000 sperm a second, they are just churning out DNA bullets all the time. To be sure all those little meiosis tadpoles are culled to safe levels, the trial is having men rely on other contraceptives while they apply the gel daily for almost 20 weeks. After sperm counts drop to sufficient levels, the men will use the gel exclusively for a year. Fingers crossed they don't accidentally have children to whom they'll one day have to explain they were the result of a science experiment gone wrong. Once a year has passed they'll stop using the gel and researchers will track them for six months to make sure there are no long term side effects. The trial should wrap up by 2022, and if all goes well it will be ready… for more testing. More studies involving thousands of men will be necessary before regulators like the U.S. Food and Drug Administration give it the all clear, so it's not hitting shelves anytime soon. Another birth control option for men is a good thing, choice always is unless you're Chidi from The Good Place. But what does this mean for women? All the birth control options I mentioned for them are much more invasive than a rub on gel, and each has their own drawbacks, like side effects from changes in hormone levels, scarring from implants, or pain when an IUD falls out of place. If this trial goes well could they have a gel too? As it happens the same company developing this gel is working on a progestin and estradiol gel for women. So a more convenient birth control could be on the horizon for women too. Or this gel could eliminate the need for female birth control all together. Maybe if the man in the relationship uses this gel for birth control, then his partner can stop taking birth control all together if she so chooses. Whatever happens, just stay safe out there. Would y'all use this? I know I would… if there was a need. I have a condom at home in a glass case that says “break glass in case of miracle.” For more sexy science, check out this playlist, and I'll see you next time on Seeker.