She did not hit #1 until she had videos showing a lot of skin and sex appeal as well as explicit lyrics. I'm talking about national and international fame, not regional fame. Controversy, shock treatment helps to sell the product, or at least gain exposure in order to sell the product. A non-sexual Gaga in all things would have been a different story.
Men have explicit lyrics in their songs all the time
. Rock and roll is chock full of songs with sexual innuendo, if not outright making it clear what they're singing about. Gaga and Beyonce aren't really doing anything different in that regard. Same with the shock value aspect.
Also, men have had plenty of music videos that feature women walking around all scantily-clad. I don't know about Gaga's career, but at least in Beyonce's case, given how much control she seems to have over her career, how she looks in her videos is her decision. To say nothing of the fact that a woman showing skin isn't a bad thing in and of itself, either.
I'll agree that the media tends to be awfully skewed in that women show more skin than men do, and in some quarters that's unfortunately an implication that all a woman is good for is to look sexy and nothing else. But I don't think that's the case with Beyonce, or Gaga, for that matter. And artists can't really
make people get them to number one on the charts (outside of heavy duty promotion, but even then, that's still not a guarantee), there's all sorts of factors as to why songs hit it big. So the fact that people might buy a female artist's music simply because they look sexy is on them, not the artist in question.
Though I also think it's rather simplistic to say that that's the only reason for why a female artist would be popular. Gaga also has a strong, commanding presences and some catchy as hell songs (at least, in some people's eyes-I like some of her songs, personally). I'd say that's played a pretty big role in the success as well. Same, of course, with Beyonce.