German design graduate Rebecca Weiss has won a James Dyson Award for a male contraceptive device called Coso, which uses ultrasound waves to temporarily halt sperm regeneration.
Weiss's Coso device is designed to be a reversible contraceptive solution. To use it, a person would fill the device with water up to the indicated mark, turn it on so it heats to operating temperature, and sit for a few minutes with their testicles dipped into it.
Coso is a male contraceptive device that applies ultrasound waves to the testicles
The ultrasound waves temporarily halt sperm regeneration, with contraceptive effectiveness beginning two weeks after the first application.
The effect is reversible, with fertility expected to return no later than six months after the last application. Weiss began designing the male contraceptive device after being diagnosed with a cervical cancer precursor that meant she could no longer take the pill.
When she and her partner looked for alternative methods and found there were no male-centred options beyond the condom or a permanent vasectomy, she started exploring the topic as part of her master's thesis in industrial design at the Technical University in Munich.
The designer imagines making it in different colours
"The problem is not unique to me personally," she said. "It affects many others as well. This is also evident in the current growing public discussion about the lack of contraceptive alternatives."

Her design for Coso is ba...