Type #1: Deeply religous (aka troubled) individuals. "How is it possible that anyone can not believe in a/my God?"
Type #2: People who love kids. It's simply incomprehensible that some of us actually don't think they are angelic and want to be around them. Two answers I always hear when I expressed that I do not desire having kids:-
(1) Oh, you will feel differently when you get older. Trust me, at my age, I highly doubt I will change my opinion, barring unforseeable changes in hormones... even that is highly unlikely.
(2) You will feel differently once you see them. Ugh, do these people ever read/hear the news? Did they not hear about the woman who systematically drown her five kids? I am not saying that I want to kill my own offspring, just making a point that some people really should not be parents. And it's much better that they are aware of that, before the mishap.