BarbaraHudson writes Researchers at the University of Kansas and Harvard are working to give men more choices for avoiding unwanted pregnancies. From the article: "H2-gamendazole keeps sperm from maturing. The unfinished sperm fragments are then reabsorbed into the testis, never ending up in the semen. 'If there's no sperm, the egg's not going to get fertilized,' says Joseph Tash, a reproductive biologist at the University of Kansas Medical Center. Almost two years ago, the FDA reviewed the compound, and now the agency wants Tash to investigate if the compound remains in the semen and whether that would harm a woman if it ends up in the vagina. Jay Bradner, working with other anti-cancer researchers at Harvard, discovered that the JQ1 molecule blocked a bromodomain in cancer cells, causing them to forget how to be cancer. One side effect is that JQ1 also obstructed a testicle-specific bromodomain called BRDT, making the sex cells that would otherwise produce sperm non-functional — mice treated with JQ1 can hump with abandon yet generate zero mouselings. Researchers are looking for a version of the molecule that works on the testicle protein only, to avoid any weird side effects."