Kiddos

I have a question for the generation below me (let's say, anywhere from 25-40). Why do so many of you, when posting on Facebook, call your children "kiddos"? Why not children or kids? I'm just curious, because it seems to be the "in thing" these days. Most of the women (just women, I haven't seen a single man call them this) call them kiddos. There must be some unwritten code that I'm no longer privy to, being much older...I guess I'll have to start calling my grands "grandkiddos". Okay, that just sounds stupid.