Please read this! It's very important message from Katy, a Catholic girl who wants to be a grade school teacher.
Please note beforehand that it's not the Catholic teaching to abstain from sex from your spouse unless a physician deems you can't safely do it without getting an STD (and that's not a Doctorate in Sacred Theology, while most of them are celibate!).
While it is unlikely a couple will have 20 kids, two families in my parish have 10 apiece. Most have 2 and their done young, which is a serious sin.