sports - tennis, gymnastics, ice skating, basketball, soccer, etc. Plus, there's less coverage and money involved so the drug testing probably isn't as rigorous and athletes failing tests aren't as high profile.
I'd imagine Olympic track and field events would have the most overlap of men and women equally doping because of how much doping can help in those sports. However, I think WADA and the Olympics keep a lot of that in check. I have no clue about the statistics though for how many men v. women are busted in the olympic sports.