Nope. See that Gravitation doujin in which the pink-haired faggot deep-throats a giant wang in X-ray vision, or Gamerz Heaven doujin in which the lead gets gangraped by strangers until the bar floor is pretty much entirely covered in cum.
All drawn by Gravitation author (who is, yes, a woman) and requested by the (yes, female) fans.
95% of non-muscle yaoi is drawn by women. That's all.