Cornell University researchers report that a compound known as JQ1 temporarily disrupted meiosis in male mice, halting sperm production during treatment and allowing sperm production and fertility to recover after the drug was stopped. The work was published April 7, 2026, in the Proceedings of the National Academy of Sciences.
Cornell University scientists reported results from a six-year, proof-of-principle mouse study exploring whether male contraception could be achieved by targeting meiosis, the specialized cell-division process that produces sperm.
According to the research team, they used JQ1, a small-molecule inhibitor originally developed for research into cancer and inflammatory diseases, to interfere with prophase I, a stage of meiosis. The researchers said the disruption caused developing germ cells to die at that stage and also interfered with gene activity needed for later sperm development.
In the experiments described by Cornell, male mice received JQ1 for three weeks. During treatment, sperm production stopped completely, and key features of meiosis—including chromosome behavior during prophase I—were disrupted.
After the treatment ended, recovery began. Cornell reported that within about six weeks, most normal meiotic processes returned along with healthy sperm production; the treated males were then bred and found to be fertile, producing healthy offspring that were also able to reproduce.
The researchers cautioned that JQ1 itself is not suitable for use as a contraceptive, citing neurological side effects, but said the mouse study supports the broader concept that temporarily interrupting meiosis could be a path toward a nonhormonal, reversible male contraceptive.
