For too long, dudes have been stuck with two (self-directed) birth control extremes: single-use condoms or nearly-permanent vasectomies, versus more than a dozen possibilities for women. But new research may be leading us toward a future with more ways for guys to shoulder some of the pregnancy-prevention responsibility. Before you get too excited, know that the study, published recently in Science, used mice (not humans). Some of the rodents' genes had been altered so they weren't able to produce some key sperm-related proteins. This left those mice with sperm that were "inflexible," making them infertile. Then, the team gave regular, non-genetically-altered mice an immunosuppressant drug that mimics the effects of the first group's DNA alterations. This time, the mice became infertile after five days of treatment — but they regained their fertility after a week without the drug. This is especially interesting because it suggests a way for us to create a long-lasting (but reversible) male birth control option. So yes, this study was done only in mice, which means we're a long ways away from seeing the same technique used in humans. But humans have the same proteins present in their sperm, so the researchers are hoping the effect will be similar in us larger mammals. Another intriguing option that's popped up recently is Vasalgel, which is a gel that interferes with sperm flow in the vas deferens. Although it's not on the market yet, the optimistic company behind Vasalgel says we may see it by 2017. Of course, neither of these options would protect against STIs, so condoms aren't exactly going extinct anytime soon. But because women already have quite a few hormonal and non-hormonal options to choose from, we welcome anything that distributes the burden of birth control a little more equally — and with more flexibility.