Scientists have developed a method to temporarily halt sperm production without damaging surrounding tissues, an advance that could lead to a safe, long-acting and reversible male contraceptive. Existing contraceptive methods are mostly female-centred or permanent, with men relying mainly on condoms and vasectomies.
A proof-of-concept study conducted on mice over six years shows that interrupting a natural checkpoint in meiosis, the process responsible for producing sex cells, can temporarily stop sperm formation. Researchers used JQ1, a small molecule originally developed for cancer research, to interfere with a specific stage of meiosis.
In male mice given JQ1 for three weeks, sperm production stopped completely. When treatment was discontinued, recovery followed within six weeks, with sperm production returning to normal levels. The mice could breed after treatment, producing healthy offspring that were also capable of reproduction.
“We are practically the only group that is pushing the idea that contraception targets in the testis are a feasible way to stop sperm production,” said geneticist Paula Cohen, an author of the study published in the journal PNAS. “Our study shows that mostly we recover normal meiosis and complete sperm function and, more importantly, that the offspring are completely normal.”
In future studies, the researchers hope to develop a new form of male birth control delivered as an injection every three months. “While acknowledging the need for robust future safety assessments of any candidate drugs, these studies provide a blueprint for developing new contraceptive approaches that act safely and selectively within the germline,” they said.
