Thanks to Sady for bringing this to mind. You should read her early and often.
I was raised in a Baptist household. I was told that I should wait until marriage for sex, not because I personally wanted to, but because Jesus wanted me to.
Now, pop quiz: what is going to be more real to a teenager?
A) A combination of vaguely unrealized desires and the pressure of a boyfriend or girlfriend
I'll give away the game: It's totally A, unless you manage to sufficiently terrify your child (and I mean about hell, not about pregnancy and STDs, since that is never enough), mainly because Jesus isn't real (or, if you're insistent, Jesus doesn't seem real since there's no proof that he's watching and that he cares, but it's certainly your prerogative to think both of those things), and their partner and/or physical desire is. Now, when the only reason you've given them to hold off on sex is that Jesus wants them to, and they're not sure if they want to, and they're with someone who is very sure about it, Jesus is going to start looking like a pretty crappy reason not to, largely because he is. Now, if they have been taught to think about their own desire, and to think about whether or not this person is someone they want to have sex with, to think about whether they've taken sufficient precautions against pregnancy and disease, and to think about whether they are ready for sex at all, then they just might make an educated decision about it.
Now, whether or not religion is important to you, and regardless of your personal take on faith, your child deserves better than this. Your child deserves to be able to think about what they actually want. Whether or not you know it, by teaching these lessons, you are setting your daughters up either to deny their own wishes by not having sex when they actually want to and are ready to or, worse, by not being able to be aware of whether or not they want sex, and doing it anyway. If they haven't been taught that their bodies, that their desire, is important, then it will not factor in when they have sex. I know that the thought of your daughters having sex isn't a pleasant one, but, for their sake, consider if it's worth her being in bed with someone who tells her that it's better when she doesn't move (that's both in Sady's post and verbatim from my first partner), or being in bed with someone who won't use a condom and not being able to articulate why that is wrong since condoms are for dirty whores who plan. Is that a pleasant thought? That's the price of not talking to girls about the validity of their feelings. The vast majority of them are going to have sex. Whether or not their earlier experiences (and, for many of them, all of their experiences) are pleasant, consensual, and affirming of their agency, as opposed to confused, unpleasant or painful, and an expression of what someone else wants (the same as abstinence would be) is up to the way that they are taught.
As a bonus, they're being set up to not be able to identify when they're raped because, if most experiences are unpleasant, it makes it harder to tell since many sexual experiences are a violation of their unspoken wishes, and there is not much physical difference between that and a violation of their expressed wishes. It's fucked. Up. Don't set your kids up for that.
All of the connections between this and reproductive options are discussed in the post, but I just wanted to talk about the incredible amounts of damage done by the mindset that the main reason not to have sex isn't one's own desire not to or the negativity of a situation, but, rather, that Sky Daddy condemns it. Thanks, rape culture!