What about the old sexist, abstinence-only bullshit line that goes something like, "A penis is like a key: If it can open a lot of locks, then it's a good key. Your vagina is like a lock: If you open for too many keys, then it'll break."
It's funny because I can twist it around and say, "A vagina is like a pencil sharpener: If it lets in all the pencils it wants to, it's a good sharpener. Your dick is like a pencil: If you sharpen it too much, it'll break and have to be thrown out."
I've heard two equally sexist arguments along these lines that coincidentally also only apply to girls.
In one analogy, a preacher/speaker plucks the petals off a rose one at a time and compares every sexual experience--depending on how hardcore fundie the speaker is, it can be anything from open-mouth kissing to groping to all sexual activities--to another petal being plucked off. And then you can't put the petals back on, no matter how much you try, so once you've done these things you're sullied forever and nobody--no MAN!!--will want a rose without petals. Totally not a convenient vagina analogy, either, amirite?
The other is comparing a girl to a piece of buttered toast that every guy she's with takes a lick of the butter off of. The more guys she's been with, the more people have licked off more butter and she becomes disgusting and in the end, nobody wants a piece of toast that dozens of other people have licked the butter from.
They only ever focus on women's virginity. Some sects pay attention to men's virginity, but for the most part it's just girls they're hung up on, probably because they have that handy-dandy, conveniently inaccurate hymen as an indicator of virginity which most girls break in childhood anyway.
