because i'm a nerd...
http://www.nytimes.com/2009/04/21/science/21horse.html?hp
Dr. Kirkpatrick, 69, has been using the birth control drug porcine zona pellucida, or P.Z.P., since 1988 to control horse and deer populations. He has been promoting its use for the federal government’s wild horses of the West for almost as long, with no luck yet.
While other approaches to birth control or sterilization are hormonal or chemical, P.Z.P. is an immunocontraceptive that creates antibodies that do not allow the sperm to attach to the egg.
I wonder why they don't use PZP on humans?
Dr. Kirkpatrick, 69, has been using the birth control drug porcine zona pellucida, or P.Z.P., since 1988 to control horse and deer populations. He has been promoting its use for the federal government’s wild horses of the West for almost as long, with no luck yet.
While other approaches to birth control or sterilization are hormonal or chemical, P.Z.P. is an immunocontraceptive that creates antibodies that do not allow the sperm to attach to the egg.
I wonder why they don't use PZP on humans?