My best friend & her older sister both are dating younger guys. But they are both in the 1-3 year range. I don't think much about it.
What I found extremely wierd was my brother dating someone younger than me. At the time I was probably around 21, and he was dating an 18 year old. I was like

. It kinda grossed me out, especially since my brother is MUCH older than I am.
I personally like either someone my age or older...but I wouldn't turn down a younger guy (within a 1-2 year age range) if I was attracted to him.