Male ‘Pill’ Still a Ways off
An effective male contraception pill seems to be in the future, but progress is being made. Many scientists are focusing on testosterone, a male hormone which is responsible for sperm production. While excess testosterone halts sperm production, any overabundance of sperm in the body does not last long enough to cause even temporary sterility.
Go here for a good description of current efforts, including how skin patches and gels could shut down the body’s production of testosterone.