Men in Sydney, Australia will be among the first in the world to try a new contraceptive giving them control over their own fertility.
ANZAC Research Institute at Concord Hospital has begun testing a new twice-monthly male contraceptive injection.
It works exactly like the female contraceptive pill by shutting down the reproductive function.
The contraceptive tricks the brain into thinking it has already produced sperm and does not affect men's sexuality.
Earlier studies have found the injection works in 95 percent of men and allows users to become fully fertile within three month of stopping the injections.
Sydney is one of 10 centers, including Melbourne's Prince Henry Institute, to take part in the worldwide trial.
Lead researcher Rob McLachlan said the treatment kept men's testosterone levels normal while the hormone progestin fooled the brain into not producing hormones needed to stimulate sperm production.