What are the REASONS for wanting no childs or waiting more than 3 years?

You're right. I rarely react the way I did to your post. Perhaps that should give you a clue.

And if you read mine carefully, you will see that I was employing the same twisted reasoning that you were in your question. That is all. So it wasn't me being personal, but rather showing you what your logic suggests.

It has nothing to do with "the girly thing" (adults call that "menstruation," thank you). And though you say that you are referring to a married couple, I'm saying why hold off on marriage? Why not get married off and start reproducing at 12? That's what waiting=murder suggests.