Women Kill Superhero movies?

I was driving back with my wife the other day (the one i never think is actually listening when i talk about comic book stuff) and we are discussing the Villains that will be in The Dark Knight Rises.  I stated that two interesting choices would be CatWoman and Harley Quinn.  She said, "Eh." 
 asked her why, wouldn't she love to see women in the next Batman movie?  Especially since all the costumed characters have been women up until this point? 
She turned to me and said something more profound than i ever expected, "Ya, I would, but every time they put a woman as a lead roll in a comic book film, it tanks!" 
I thought about this, not wanting to believe it, but i had a hard time refuting the statement!  The movie that have starred comic women (CatWoman, Elektra to name a few) have ALL done horribly in the box office.  Even the movies that have done well have to seem to downplay the importance of the women, such as X-men (where they totally wasted Storm's character) and Fantastic Four (Which didnt do that great but managed to spawn a sequel.) 
What do you think, ComicVine world?  Am i crazy or does a comic movie have to star male characters to do well in the box office?