The pill and the condom, whether used separately or in combination, have been the most popular method of contraception for men and women for decades. The efficacy of the pill and condoms range from 92 to 98 percent, respectively, but with side effects. Synthetic hormones in the pill can have very real side effects on the body, while condoms can be prone to slippage and breakage.

Now, a study published in the journal Protein Expression and Purification suggests science is one step closer to developing a non-hormonal male birth control pill — without the side effects.

“The challenge in developing a new contraceptive is that a male ‘pill’ will be taken by perfectly healthy men,” said John Herr, author of the study and a cell biologist at the University of Virginia School of Medicine, in the statement.

He added: “Because of this fact, a male contraceptive drug should be very precise in its mechanism of action, without any off-target side-effects on molecules with similar properties located in other organs.”

To develop a non-hormonal male contraceptive drug, Herr and his colleagues managed to isolate and manufacture an enzyme known as spermatids (TSSK2) which are exclusively found in the testes, and involved only during the very last stage of sperm production. The researchers sought to target this particular enzyme to inhibit its function as sperm is made, and essentially, prevent egg fertilization. This will improve the likelihood that targeting the enzyme will have effects nowhere else in the body.

Similarly this month, researchers at the University of Illinois at Chicago, have developed an injectable non-hormonal and reversible male birth control gel, Vasalgel, that will prevent the sperm from getting through the vas deferens — the duct that conveys sperm from the testes to the urethra. Once the birth control is injected, the material forms a hydrogel, remaining in a gel-like, soft state that can flex to the walls of the vas deferentia. Although water soluble molecules can pass through, it blocks larger structures, like sperm. Researchers suspect it could lower the occurrence of hydrostatic pressure, or the back pressure in sperm production areas. Vasalgel is expected to be on the market as soon as 2018.

Herr admits much work remains to be done with his drug, but he remains hopeful based on the recent breakthrough.

"We're on the path toward the male contraceptive drug, and this is a noteworthy benchmark along that path,” he said.

Previously, Herr developed SpermCheck, a home fertility test for men that is sold in pharmacies and stores around the world. A positive test result means a man’s sperm count is at least 20 million per milliliter. Typically, about 90 percent of fertile men have sperm counts above 20 million per milliliter, which are counts needed for conception. A negative test indicates sperm count is less than 20 million per milliliter. On average, 10 percent of fertile men have sperm counts below this mark, meaning a negative test is not 100 percent definitive.

New male contraceptives and home fertility tests are all part of the evolving contraceptive revolution — with the pill no longer being only synonymous with women, but with men too.

Source: Herr J. et al. Milestone reached on path to new form of male contraception. Protein Expression and Purification. 2016.