This contraceptive lets men literally switch their fertility off and on

Imagine if there were a type of birth control that could be activated by a button. A German carpenter invented a device that sounds like it came straight from science fiction—male contraception that allows a man to turn his sperm flow off and on with just a flick of a switch. Clemens Bimek first came up with the idea of a spermatic duct valve around 20 years ago while watching a documentary about contraception. According to German magazine Spiegel (via The Telegraph), Bimek filed a patent in 2000, then built the first prototype of the Bimek SLV in 2006. “Many of the doctors I consulted didn’t take me seriously. But there were some who encouraged me to go on tinkering and helped me with their expertise,” he said. During a half-hour operation, tiny valves are implanted in the vas deferens and controlled by a switch that is easily accessed by hand through the scrotum skin. The Bimek SLV website describes the switch as being “as small as a gummy bear.” When the valve is closed, sperm cells are prevented from being released during ejaculation, leaving the seminal fluid sterile. The result is similar to a vasectomy, except the patient can allow the sperm to flow at any time whereas vasectomies sometimes cannot be reversed.