Ultrasound-based male contraceptive encourages gender-balanced approach to pregnancy

The design is a reversible and hormone-free device that is safe for home use and works to temporarily inhibit sperm regeneration

Spotted: There are significantly more contraceptive methods available for women compared to men. To be precise, there are around 12 female contraceptive methods, ranging from IUDs, the pill to fertility tracking, yet only two options for men: condoms or a permanent vasectomy. 

German design graduate Rebecca Weiss has designed an ultrasound-based, reversible and hormone-free male contraceptive device for home use, which functions by temporarily stopping sperm regeneration. Named Coso, the drive has won a James Dyson Award.   

Coso is a reversible contraceptive solution, similar to an IUD for men in that its effects wear off after a specified time. Operating the small bowl-like device is fairly straightforward. First, it is filled with water and turned on, at which point it starts heating up until reaching operating temperature. The user would then sit for a few minutes with their testicles dipped into the device.

Coso uses ultrasound to modify sperm mobility and temporarily inhibit the production of new sperm, meaning that a female egg cannot be fertilized. The device is designed for safe, at-home use and is effective two weeks after the first application. There is also an accompanying app to monitor progress.   

After being diagnosed with a cervical cancer precursor, Weiss could no longer use hormonal contraceptive methods and soon discovered that options for men were severely lacking. Taking the matter into her own hands, Weiss decided to develop a new method of male birth control as part of her master’s thesis in Industrial Design at the Technical University in Munich.  

During the research period, Weiss discovered that ultrasound contraception was successfully tested on animals in a 2012 study by the Parsemus Foundation, but remains untested on humans. Although Coso is only a concept at present, Weiss hopes that it will encourage further research on humans. Her next challenge is sourcing financial support for clinical trials so that Coso can be realised as a contraceptive for mainstream use.  

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