Chemically Freezing Sperm Tails Could Be the Key to a Reversible Male Contraceptive

As sperm swim they transform chemical energy into motion, the way a car’s engine uses gas to propel you down the road. Like that engine, the process is complicated—if just one part stops working, the whole system can grind to a halt. This idea might lead to a contraceptive for men that’s reversible. »10/01/15 7:40pm10/01/15 7:40pm