When it comes to contraception, women have their pick of techniques. In addition to sperm-blocking barriers and foreign objects in the uterus (IUDs), there are about a million ways to pump extra hormones into the bloodstream (pill, patch, ring, shot, or implant).
For men, it's always been pretty much condoms or a vasectomy.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.