From vasectomies to the male contraceptive pill, there have been many attempts to shift the burden of birth control burden onto men. Now one German entrepreneur believes he has the solution – a ‘switch’ to stop sperm from reaching the penis. The valve – which is implanted internally is designed to divert the flow of sperm back to the man’s testicles, making him temporarily infertile. If he later decides he wants a wants to become a father, he simply locates the implant in his scrotum and flicks the switch back, allowing sperm to be ejaculated.