Look around.
I am willing to bet that you can think of several people just in your town that shouldn't have had kids.
God granted humans the ability to think for themselves.
It is between that person or couple and God. Any preacher who says otherwise or just comes up with things, as this preacher did in this case, is flat out wrong.
Most of the couples who shouldn't have kids shouldn't have got married, shouldn't have got together in the first place.
If you miss them in town, turn on Jerry Springer, et al and you'll see a whole bunch of people who are so selfish and screwed up they should never have procreated.