Reciprocal NeedsPregnancy risk sex goes beyond simple barebacking. Barebacking is basically a selfish, lazy thing -- don't want to wear a condom, and just want to appeal to one's own pleasure. One can bareback with birth control, and not risk pregnancy (or at least, lower the risk).
Pregnancy risk sex requires stalking the woman and getting familiar with her menstrual cycle, and watching carefully for signs of ovulation. It also requires arguing against birth control, so you know she's fertile. You **** her for the days before she ovulates, and every day till a few days after, just to make sure there is motile ***** in her when her egg(s) are released.
You have to be in good condition, too, and not smoke or drink so that your ***** is in top form and health. And you have to encourage her to do the same, so she's at the peak of her health. And you need to know what turns her on, what can make her unable to resist, and make her accept you ******* inside of her. That's quite a lot of work, even if you're into forced sex scenes!
If she's into it too, then it can be crazy-fun for everyone. Of course, making a baby is a big, big responsibility, and this sort of thing has serious repercussions for all parties involved. All in all, doing it as a fetish role-play is likely the hottest solution -- but that requires you to find a compatible partner, and until then, a lot of planning and plotting inside your head.
That's true for men as well as for woman. I've always been turned on by men who lust after the probability of impregnating me; men who lie about pulling out, or play at stalking and raping me. It's not at all one-sided, not in the least ... and it's not just about being lazy about birth control or making the move toward sex. My preference is for men who can't get off without knowing there is a chance to knock up the ***** he's *******. I know, it's a lot of requirements for a successful hook-up, but there are plenty of men with this need, just as there are plenty of women with a reciprocal need.