German Carpenter Invents Device that Lets Men “Shut Off” Sperm

German Carpenter Invents Device that Lets Men “Shut Off” Sperm
Science & Medicine

No condom? No problem! Don’t want to have a vasectomy? No worries! Guys don’t have to become a baby daddy. Men who want to avoid fatherhood will soon be able to do so with just the flip of a switch.

But installing the “sperm switch” is still quite invasive, so don’t get too, um, excited just yet.

The Bimek SLV device, named after Clemens Bimek, the German carpenter who invented it, is “as small as a gummy bear.” Surgically implanted and attached to the spermatic ducts the device has a valve that can be opened and closed with a switch that can be accessed from the scrotum’s skin.

Closing the valve diverts sperm cells by pushing them off to the side, which prevents them from reaching the seminal fluid, leaving the man sterile upon ejaculation. It sort of works like a vasectomy, except you can’t always reverse a vasectomy, and doing so requires complicated surgery.

It takes about 30 minutes to insert the device under local anesthesia.

The company’s website explains:

“Each spermatic duct is transected, then the newly cut ends are connected to the valve casing using specially developed instruments. The spermatic ducts are then put back into the scrotum and the inner and outer dermal layers are sealed – then you can head home.”

There’s a “safety pin” included in the device to make sure it doesn’t turn on accidentally. [1]

Once the SLV is implanted, sperm cells may still be present in ejaculatory fluid for up to 3 months, or 30 ejaculations – whichever happens first. It’s recommended that men who get the SLV implanted have a sperm analysis with a urologist before they fully depend on the device.

The switch is made of mostly PEEK Optima, a biomaterial used for medical implants like cranial and dental implants.

If a guy decides he wants offspring the next day, he can just flip the switch and open the valve.

Bimek says he came up with the idea 20 years ago while watching a documentary about contraception. He filed a patent in 2000.

“Many doctors that I have consulted, have not taken me seriously,” Bimek told Spiegel. “But there were also some who have encouraged me to continue to tinker and who have supported me with knowledge.”

The Bimek SLV can’t be sold in the United States just yet; it still has to go through the Food and Drug Administration’s approval process. While Bimek had the device implanted in him in 2009, the SLV still has to go through clinical trials on humans. The first tests of the device will happen with 25 men this year.

Philipp Renger, who is in charge of marketing the SLV, had one implanted, too, but it wasn’t a very pleasant experience. He said it was hard to open and close, so Bimek had to redesign the gadget, and Renger had to undergo follow-up surgeries.

“It sounds terrible … but it worked really well,” Renger said.

Design aside, the SLV implanted is not a risk-free procedure; the valve could lead to scar tissue development in the seminal ducts, which could stop sperm from traveling through the tubes and cause long-term infertility issues.


“Half way through and searching for condoms? Need to insert your diaphragm? Forget to take the pill? Is your fertility window really over?” the website asks. “What if you could simply forget about contraception? We want you to be able to concentrate on what’s important, spending time together without having to worry about contraception. To simply let go and enjoy.” [2]

You can let go and enjoy…as long as you’re sure you or your partner don’t have an STD. The SLV can’t protect you from those.


[1] The Huffington Post

[2] Mashable