Bradley,
You might want to consider the new options of male birth control for your objectives. It looks pretty promising.
http://www.nlm.nih.gov/medlineplus/news/fullstory_14198.html
Male Contraceptive Success in Australia
Monday, October 6, 2003
SYDNEY (Reuters) - Australian researchers said on Sunday they had conducted a successful experiment using two hormones to suppress sperm production, which they said could lead to the first injectable male contraceptive.
Men in the trial of 55 couples received hormone treatment over the course of a year using a combination of the male hormone testosterone and progestin, which is used in female contraceptive pills.
Scientists from Sydney's ANZAC Research Institute and the Prince Henry Institute of Medical Research in Melbourne said the aim of the trial had been to "switch off" male sperm production.
None of the men's partners became pregnant during the trial and none showed any side effects. The hormone treatment was the only form of contraception used during the trial, they said.
"This is the first time a reversible male contraceptive that will suppress sperm production reliably and reversibly has been fully tested by couples," the institute's principal investigator professor David Handelsman said in a statement.
He said a testosterone implant had been injected every four months and a progestin had been injected every three months.
"This shows the way for a final product to be a single injection containing testosterone and a progestin which will easily be given by local doctors on a three-four monthly basis and still maintain male sexual health," Handelsman said.
Developing an effective and convenient male contraceptive has been difficult, in part because of the rapid rate at which men produce sperm.
A recent British trial showed promise but side effects stopped the trial.
Testosterone is often linked with virility but treatment with the hormone can suppress the production of sperm by reducing levels of hormones called gonadotropins.
Too much testosterone can have harmful effects, such as reducing levels of the "good" cholesterol HDL. Experimental male contraceptives often include another hormone, such as a type used in female contraceptives, to block side effects.
Skipper