This male birth control worked for over a year (in monkeys)

Nearly half of all pregnancies in the United States are unintended. That's 2.8 million pregnancies a year, at least as of 2011—and that's the lowest it's been in three decades. We have better contraceptives (and more access to them) to thank for that decline, but if 45 percent of all pregnancies are accidental, there's still a lot of room for improvement.