My DD is 18mo and she does this too...so I'm interested in the replies. The thing is that my dd goes to day care and everyone the works there is a woman. And the majority of people I hang out with are women (sis, Mom, girl friends). The only men she hangs out with are my dh and his guy firends and they're always in the garage playing with cars or something. So I kind of attibute it to that. Mostly it's weird for us becuase until about amonth ago, DD would wave and say hi to EVERYONE. I just chalk it up to a stage and it will pass.