Can a bath for testicles prevent pregnancy?

COSO is an ultrasound based contraceptive

An innovative ‘testicle bath’ could be the future of male contraception.

Many men would like to take on more responsibility for preventing pregnancy but the options are often seen as limited to just condoms or a vasectomy.

Now a new unexpected form of contraception is in development. COSO is an ultrasound-based, reversible and hormone-free male contraceptive device that looks like a small bath.

German design graduate Rebecca Weiss came up with the idea after having to stop using hormonal contraception following a cervical cancer diagnosis. She and her partner looked for alternative methods and were frustrated by the limited options available for men.

"There is a current growing public discussion about the lack of contraceptive alternatives. So I decided to deal with the development of a new contraceptive approach for men."

Rebecca Weiss, COSO

As a result she started exploring the topic as part of her master's thesis in industrial design at the Technical University in Munich.

The 'bath' is for home use and temporarily stops sperm production using ultrasound waves - with contraceptive effectiveness beginning two weeks after the first application. The effect is reversible and fertility is expected to return no later than six months after the last use.

Once set up by a doctor, the user fills the COSO bath with water heated to operating temperature. They then bathe their testicles for a set period of time. The device can be monitored in real-time via the COSO app and once the treatment is complete, the device switches itself off automatically.

The ground-breaking device won the prestigious James Dyson Award in 2021, but in order to launch COSO as a contraceptive to the market, it needs financial support for clinical trials.