We actually have an ultrasound of Charlotte sucking her thumb in utero. When she was born she never enjoyed the pacifier- she went directly to that left thumb. Everything that I have read about thumb sucking strictly warns against any power struggles with thumb sucking, it has to be the kids decision to stop.... or they wont... plus all kinds of long term psychological damage and whatever. So I have never said anything about it, but set it up about a year ago when she wanted her fingernails painted. "That would be fun Charlie! We could paint them bright pink. But you know... you cant suck your thumb if your nails are painted." Immediately she decided that she did NOT want them painted, not even for hot pink, hot pink with sparkles. So I have just been letting it ride. She will bring it up every once and a while out of the blue to myself or random strangers, "I can't paint my fingernails, cause I still suck my thumb." I know how badly she wants her nails...