See, that was my point. They still do, because it's sexy and that is the only thing they want to matter in that moment. With penalties you are trying to make the signal from the person's rational brain strong enough to override their lizard brain, in a moment when the lizard brain is emitting very strong signals already.

It works somewhat, but to a much lesser extent than, say, penalties for driving without carrying a warning triangle, which is a rational-brain activity. At some point the penalties are creating a cost that is bigger than the cost of dealing with the thing they are trying to prevent, while still not working all that well.

Anyway, that's extremely off topic. I think the point is that there's no shortage of babies wanting to get made, and if you want the population to make more babies, you should reduce the things that are preventing them from doing so, not add positive incentives (unless they cancel out negative ones).