Okay, yes. Sex sells. As a female GM, I use this simple fact to my advantage.
...No, my sessions are not red-hot X-rated phone sex.
Simple fact: Men will RP romance with a female GM that would squick them out to play with a male GM. Women don't usually seem to care much one way or the other. So a female GM has a larger emotional space to work with than a male GM.
Another simple fact: Merely hinting at sexual themes is enough to rivet the attention of most gamers. When they say "sex sells," they don't mean that they're going to show you naked people driving a Mercedes. They show good-looking people getting into the Mercedes, implying that you, too, could entice beautiful people into this car if you owned it. And like in the horror genre, it's generally more powerful to imply that certain things could happen or are happening, and then leave it up to the individual imagination, rather than spell it out in unnecessarily graphic detail.
How this is different from "action hero pin-ups": All of the above applies to people, both men and women, and is a tool to increase their interest and participation in an RPG. It also adds an important, often neglected personality component to PCs and NPCs, if it's handled with maturity.
"Action hero pin-ups" are just pure wank fodder. The heavy use of display poses, and startled and/or threatened expressions gives the lie to the assertion that these are competent heroines engaged in butt-kicking. These are CGI porn stars in hero costumes. While I don't find anything inherently morally wrong in wanting a picture of a CGI porn star in a hero costume, I'm somewhat offended to find it in an online gaming store rather than a fetish emporium. About the last thing I really want to see in a gaming store, as a female gamer, is more of this "woman as nothing more than a vehicle for the man's desire" crap.
It's the Internet. There is real porn out there. Go find it. Get out of my gaming store.