Here's what he said to Variety:
It's made it pretty clear that there's a gigantic market for movies like "Bridesmaids" and movies that star women or are intended for a female audience. People assume that men will drag women into every hardcore action movie out there and that occasionally a woman will drag a guy to a romantic comedy. There's an enormous amount of stereotypes which aren't true in our industry. If you make a strong movie, which appeals to a female audience, then people will want to go see it. Most (follow-up) movies aren't good, so the only way that this trend will continue is if somebody makes another great movie. I'm sure it will happen, but it won't happen just because they're trying to make a movie with women or for women. Usually what happens with a trend like this (is) the next few aren't very good. And then people say, "Was that a fluke?" It wasn't a fluke. People just like good movies.
People do like good movies. But the point I disagree with is that movies about men that do well get made over again and the follow-ups usually suck but they are never said to be flukes. It's just business as usual. Hardly any movies targeted at women ever get the chance to make a sucky follow-up (except for Sex and the City). When the first one is a success it is called a fluke. Women's successes are still seen as anomalous.
Q&A with Judd Apatow (Variety)