A new study adds to the mounting evidence that when it comes to the biology of HIV, sex matters. Johns Hopkins University researchers found that women for whom injection drugs were the likely transmission route progressed to AIDS with smaller amounts of HIV than did men with similar backgrounds. At viral loads that equaled mens’, women had a 1.6-times greater risk of AIDS. Researchers are next set to determine whether this holds true for the non-drug-using population, as well as whether treatment strategies for women should be adjusted accordingly.