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.


Some doctors have questioned the safety of the device. “My assessment is that implanting the valve could cause scarring where it meets the vas deferens,” Wolfgang Bühmann, spokesman for the Professional Association of German Urologists, said. He is concerned that potential scarring may prevent sperm from flowing even if the valve is switched open, and that the valve may become clogged if it is switched closed for too long.

So far, the only person who has tried the device is Bimek himself. Under local anesthetic, he was able to guide the surgeon during his own operation, which proved to be successful. The valve is set to be implanted in 25 men during trials starting this year.

Contact the author at marie.lodi@jezebel.com .