Haim Breitbart, a medical researcher at Bar-Ilan University in Israel, has developed a drug that will temporarily incapacitate sperm cells in mice.
http://www.israel21c.org/201006238085/health/a-birth-control-pill-for-men via Popular Science | Image: NIH
So far, the new pill dubbed the Bright Pill (a play on Brietbart's name) has been tested on animal models in a pre-clinical setting, and has been found to work wonderfully on mice. "What we found is that by treating the mice with our molecule we can get sterility for a long period of time; in the lower dose, about one month, and in the higher dose we found three months of sterility.
"Later on the male mouse can become fertile. It's reversible," he promises.
Provided in pill form, but also tested as an injection, the male birth control solution was administered in two treatments over three days: One day on, one day off, one day on. In the larger dose group, it took about a week until the effects manifested themselves, but most importantly, the treatment does not appear to in any way affect the sex drive or the sexual behavior of the mice who received it.
http://www.israel21c.org/201006238085/health/a-birth-control-pill-for-men via Popular Science | Image: NIH
All forms of birth control have a significant rate of failure, even abstinence. Redundant controls will reduce the risk of unplanned pregnancy.