A new male contraceptive gel is set to go on trial next year, designed to prevent pregnancy by halting the production of sperm.
More than 400 couples will test the product for the major study, due to launch in April 2018.
The trial will mark one of the largest tests on a hormonal male contraceptive to date, involving participants from the U.K., U.S., Sweden, Italy, Chile and Kenya.
Currently, contraception options for men are limited, with just two choices on the market: condoms or a vasectomy.
Perhaps surprisingly, the gel is not designed to be rubbed into the genitals. Instead, men involved in the trial will rub a small portion of the gel into their upper arms and shoulders every day, enabling it to be absorbed into their bloodstream.
The contraceptive contains a synthetic form of progestin, which prevents the testes from producing enough testosterone to produce regular sperm.
The gel also contains a synthetic testosterone replacement, designed to counteract any hormone imbalance caused by the progestin, without leading to the production of sperm.
Each participant will use the gel for a minimum of four months, and their sperm levels will be monitored by researchers.
Meanwhile, their female partners will still be able to use a form of female contraception if they wish to prevent pregnancy.
The gel has been developed by the National Institute of Child Health and Human Development, part of the U.S. National Institutes of Health.
Speaking to MIT Technology Review, Diana Blithe, director for contraception development at the organisation, said the gel dries within a minute and is easy to use.
"It's not a lot of effort. It's just remembering to use it every day," she said.
She added that even if the trial results are positive, the public will have to wait a few years before seeing the gel available on the market.