A Baby Step Toward a Male Contraceptive

Birth control options for men have been one extreme or the other: single-use condoms or a hard-toreverse vasectomy. Now researchers in China have found a method that may offer something else. When biodegradable iron oxide nanoparticles were injected into the bloodstream of male mice, then guided via magnets to the testicles, where they were heated up, spermatogenesis was halted, preventing reproduction for about a month. (This method is far more attractive than another contraceptive method that has undergone testing, the injection of heated nanoparticles directly into the testes.) The nanoparticles are eliminated naturally from the body in 30 to 60 days.