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.
The doctor that did mine; made sure that I knew that it whilst it was theoretically reversible; it is a major surgery vs a minor one to get it done, and the success rate is very low ~20%. So best consider a vasectomy as permanent and irreversible.