According to a recent article in the Telegraph, a German carpenter has invented an on-off switch for sperm as a contraceptive for men. He has had a prototype that he designed implanted in himself.
by Rachelle Megan with video from Vimeo / Bimek SLV
I foresee a lot of problems with this before it gets to market, but it is an interesting idea. I think it would be ideal for men who are almost but not quite sure they want a vasectomy and I have met a few men who feel that way. I am not sure a “rocker” switch is the way to go here. I am thinking maybe some encrypted wireless signal would be better, but if someone malicious got the password, hijinks could ensue.
German carpenter invents on-off contraception switch for sperm – Telegraph
http://www.telegraph.co.uk/news/worldnews/europe/germany/12083673/German-carpenter-invents-on-off-contraception-switch-for-sperm.html