German carpenter, Clemens Bimek, has invented a new contraceptive valve that allows the flow of sperm to be switched on and off like a tap.
The valve, which is surgically inplanted on the van deferens, the ducts carrying sperm from the testicles, works by flicking an on-off switch accessed under the skin of the scrotum.
The procedure takes around thirty minutes.
The valves are less than an inch in length and a weigh only a couple of grams.
Bimek told Spiegel magazine in Germany the idea came to him when watching a documentary about contraception.
He later discovered no patent had been filed for a valve-like contraceptive, so he began developing his own.
However many physicians he approached for advice dismissed his ideas.

No more leaky faucets. The new contraceptive allows men to turn their sperm flow on and off with ease. (Tumblr) Source: Tumblr
“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,” Bimek told Spiegel magazine.
Many doctors have raised concerns over the new contraceptive, claiming it may cause permanent scarring that could prevent sperm from flowing even when the valve is switched on.
“My assessment is that implanting the valve could cause scarring where it meets the vas deferens,” said Wolfgang Bühmann, a spokesman for the Professional Association of German Urologists.
He also said keeping the valve closed for too long may clog the vans deferens, which could lead to further health complications.
Trials for the contraceptive will be conducted later this year, with 25 men set to test the new valve.

Clogged pipes, whatever the context, are never ideal. (NBC) Source: NBC
So far, Bimek is the only man to have the valve implanted.
His surgery was conducted under light anesthetic, so he could direct his surgeon, Dr. Hartwig Bauer, through the procedure.
Dr. Hartwig believes the valve will be a hit and find this procedure preferrable to a vasectomy.
“A third of patients want to have the operation reversed later, but it doesn’t always work,” Dr. Hartwig said.