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Hank briefs us on the news that a team of biologists has developed the first contraceptive for males that is totally effective, easily reversible and doesn't mess with your hormones!

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Hello, if you were looking for me here in the office of our regularly scheduled time for breaking news, well, sometimes the news isn't breaking, ya know, when we're scheduled to break it, so now, now we have some breaking news for you. 

Today in the journal Cell, a team of American, British, and Canadian biologists say that they have developed the first contraceptive for males that is totally effective, easily reversible, and it doesn't even mess with your hormones. And I'm like getting out my wallet right now, but y- put it down for now, 'cause it's not ready to be used for humans yet. But, the researchers say that based on what they've seen in mice, the drug that they've concocted will be completely translated to men providing a novel and efficacious strategy for a male contraceptive. 

Now there are already a bunch of different efforts underway to develop male contraceptives, but most of them involve getting injections where guys really don't want needles to go or using ultrasound which isn't super convenient, or hormone treatments which hasn't been particularly effective for men and yes, even though women have been doing it since the 1960s to keep from getting pregnant, still comes with a bunch of complications and side effects.

This new method is none of those, it uses a compound that targets a single protein, found only in the testes, called BRDT. This protein is essential to a step in the sperm-making process called chromatin remodeling, in which DNA in a germ cell is unraveled and presented to other proteins that transcribe its genetic information and copy it for sperm to carry away. The new compound, called JQ1 locks BRDT from doing its job, leaving the sperm genetically defunct and therefore useless for reproduction.

According to the study, mice that were given JQ1 for six weeks had an 89% drop in sperm production, and of the sperm that were produced, only 5% were "modal" or able to swim around on their own. Now considering how many millions of sperm a male can release at a time, these numbers meant that the treated mice were effectively infertile. After 3 months of progressively larger doses, none of the males produced any offspring, but their hormone levels stayed the same and so did their mating habits. And since there was no risk of pregnancy, scientists noted that after mating, the males actually gave the females their phone numbers.  

And potentially the most exciting bit, after stopping the treatments, the mice's fertility returned to normal. The only drawback, uh, their testes shrank by about 35%, though I don't know that a lot of males have a lot of like, teste largeness pride. So may be a deal breaker for some people, but when you think about all the other issues that we've covered here on SciShow from the overpopulation crisis to the growing biomass of humanity, maybe a little shrinkage could be considered taking one for the team of humanity. 

You know, I personally, I think I would be able to deal with a little bit of testes shrinkage but I'm curious the rest of SciShow audience, what do you think? tell me how you feel about the potential, being infertile temporarily, intentionally eehh with a little bit of a trade-off. Tell me how you feel about that down in the comments. 

Thank you for watching this episode of SciShow: Breaking News. If you want more breaking news you can go to and subscribe, we'll see you next time.