For the last couple of decades, women have been treated as second-class filmgoers. The plexes have been dominated by explosions, chases, slashings, Superheroics, gross-out gags and other delights tailored to the tastes of the adolescent male and his overgrown counterpart. Now, the tables have been turned by a single franchise.

The Twilight films don't just attract audiences that are 80% female. They give vent to passions so exclusively girlish that their intensity baffles mere males. Yet on its first night out, The Twilight Saga: Eclipse ensconced itself in more American cinemas than any other film has ever managed to. The $68m (£45m) it took in the process made it the biggest Wednesday opener of all time. This also made it the most successful opener on any day of the week, apart from just one other film. That happened to be The Twilight Saga: New Moon.

In the cinemas, then, a great triumph for women is clearly being won. Just how much good it's doing them is more doubtful. The spell that Twilight casts over Twihard poppets and even their full-grown Twimoms cannot be assumed to be entirely benign.

Eclipse finds its 18-year-old heroine Bella as insecure and uncertain of her place in the world as many another troubled teen. Time perhaps for her to get a grip on her life and forge a purposeful path for herself. Perhaps she could sail round the world single-handed, set up a dotcom business or at least get on with her homework. Not Bella.

Instead of sorting herself out, she opts for escape to a parallel universe. There, she'll be able to join a coterie who'll be guaranteed to accept her. She'll have to be undead, but you can't have everything. The rescuer who'll whisk her away from the challenges of reality will, of course, be a man. Actually, Edward's a vampire, but no matter, he's incredibly good-looking. He may be a dangerous dude, but a woman's love can tame him.

Anyway, Bella's like totally in love with him, and it's this that justifies the sacrifice of her human life. After all, Edward has qualities to die for. His determination to protect Bella's best interests verges on the abusively controlling. In particular, unusually for a well-favoured suitor, he's prepared to contain his carnal urges lest their gratification harm his beloved.

A warm-blooded rival for Bella's affections is available. Like Edward, Jacob the werewolf wants only what's best for her, but he's not as handsome as Edward, so nuts to him. In a climactic argument, the two guys debate what's best for her. As they decide her future she sleeps between them, the epitome of submissive passivity.

Bella's fate isn't only dispiriting; it's also deceptive. On the whole, beguilement by a teenage bad boy, however courtly his manner, doesn't lead to eternal love; nor is self-abnegation a reliable route to bliss. It's therefore understandable that some have questioned the merits of Twilight's message for womankind.

Still, the author of the books on which the films are based, Stephenie Meyer, has answered her critics. Bella, she says, isn't "a negative example of empowerment". After all, "The foundation of feminism is this: being able to choose." Ultimately, says Meyer, what Bella does is up to Bella. That ought to be enough to qualify her as a feminist.

This seems to imply that anything a woman does is a feminist act, unless she's performing it because someone's put a gun to her head. I don't know if this is all that feminism amounts to, but then I'm only a man. Some women, it seems, have yet to be convinced.

Whatever adjudication on this point is deemed to be correct, something here seems perplexing. You can't get away from a strange paradox. Women are using their regained power over the picturehouse to trash their hard-won independence. What mysterious creatures they are.