There's a major difference between having sex and the active decision to bring another human being into the world, especially in a society where preventative, and after-the-fact, contraception is readily available. Having a child today is a conscious choice.
Well, thanks Hermann for pointing out that onei is a mom. I had assumed otherwise! lol.
That being said....
The desire to procreate is not limited strictly to the act of sex. The desire to have a child, to hold that warm little bundle of joy in your arms, is not just about screwing. It's an urge of its own, completely outside of the act which makes it possible, and if you think there are many people in this world who can simply shrug off that urge, that desire, then you're kidding yourself.