Scientists at Cornell University may be closing in on the long-sought “holy grail” of male contraception: a safe, reversible, nonhormonal method that completely halts sperm production. In a breakthrough mouse study, researchers used a compound called JQ1 to temporarily shut down meiosis—the critical process that produces sperm—without causing lasting harm. After treatment stopped, sperm production bounced back, fertility returned, and the animals produced healthy offspring.
They’re progressing slowly, but it’s obvious that they don’t want a bad launch so they’re all waiting until they have something that works and is safe enough and safety only comes from having people take it then see if it works after being reversed or ended years later.