A new form of birth control for men is showing promising results in lab mice, rendering them “temporarily infertile” via a single injectable dose, according to a study published on Tuesday in the peer-reviewed medical journal Nature.

“Nearly half of all pregnancies are unintended; thus, existing family planning options are inadequate,” says the study, which points out that the only available birth control options for people with penises are condoms and a vasectomy. 

“Most current efforts to develop new contraceptives for men impact sperm development, meaning that contraception requires months of continuous pretreatment,” the study continues. “Here, we provide proof-of-concept for an innovative strategy for on-demand contraception, where a man would take a birth control pill shortly before sex, only as needed.”

The team from Weill-Cornell, led by postdoctoral associate in pharmacology Melanie Balbach, found that injections of the new drug could temporarily pause fertility in male mice by inhibiting the movement of soluble adenylyl cyclase (sAC), a cell enzyme that “is essential for sperm motility and maturation,” according to the study. 

Previous versions of male birth control found an approximately 95% success rate at preventing unwanted pregnancy through hormone-based methods, but were abandoned due to “unwanted side effects,” which ranged in severity from acne to mood disorders. The halting of the study drew some criticism by people who accused men of being unable to handle common side effects from birth control that women contend with every day.

“Here, we now show that administration of a single dose of an acutely-acting sAC inhibitor into male mice rapidly and temporarily inactivates sperm movement and renders the mice temporarily infertile,” reads the study, who found similar results when testing on human sperm in a lab dish.

After the striking down of Roe v. Wade in the U.S., rendering the legality of safe and legal abortions to individual states, some legislatures have also decided to take aim at access to contraceptive methods. This prompted the House to pass the “Right to Contraceptive” act, which would protect access to birth control at the federal level. The bill did not clear the Senate.

It is unclear when the new birth control drug will be cleared for human clinical trials.

C Mandler

C Mandler is a social media producer and trending topics writer for CBS News, focusing on American politics and LGBTQ+ issues.