I kiss my kids on the lips. No worries. I even remember kissing my dad on the lips as a kid until I got to my teenage years and then I didn't want to kiss my parents at all, then some time after that I started again but just on the cheeks. My dad and I now exchange cheek kisses - usually one on each cheek plus another for good measure, LOL.
I don't mind my kids kissing their close family on the lips. But I have an uncle who always kisses on the lips and it GROSSES me out. I always have to deflect and go for the cheek... and still without fail he always goes for the lips next time. I am sure it is very innocent, but I am so not comfortable with it. On the other hand, I have another uncle who is more of a hugger - he squeezes the living crap out of me every time we meet (he's strong and sometimes it hurts, LOL!) but interestingly I have NO problem with this whatsoever!