Cornell University scientists have made significant progress toward what many consider the holy grail of male birth control: a safe, long-acting, fully effective, and nonhormonal contraceptive that can be reversed.

Stopping Sperm Production by Targeting Meiosis
In a proof-of-principle study conducted in mice over six years, researchers showed that interrupting a natural checkpoint in meiosis, the process responsible for producing sex cells, can temporarily halt sperm production. Importantly, this approach worked without causing permanent damage.

To achieve this, the team used JQ1, a small molecule inhibitor originally developed as a research tool for studying cancer and inflammatory diseases. Although JQ1 is not suitable as a treatment due to neurological side effects, it is known to interfere with a specific stage of meiosis called prophase 1. This allowed the researchers to demonstrate for the first time that sperm production can be safely and reversibly stopped by targeting meiosis and sperm production at this stage.

“We’re practically the only group that’s pushing the idea that contraception targets in the testis are a feasible way to stop sperm production,” said Paula Cohen, professor of genetics and director of the Cornell Reproductive Sciences Center.

“Our study shows that mostly we recover normal meiosis and complete sperm function, and more importantly, that the offspring are completely normal,” Cohen said.