Potty Training!

Ok, I am at a complete loss now. Rhett, who will be 4 years old on the 24th of Feb. still has no desire to master the whole potty training thing. He got peeing down no problem. He hasn't even had an accident at night. But getting him to do his business in the toilet instead of his underwear is just not happening. McKenna, who is almost 19 months old, wants to potty train more than anything. She throws a complete fit when she is forced to put a diaper on. That doesn't last long though, because she has figured out how to get out of everything and wants to be naked all day. She will go in and sit on her little potty and has even peed in it a coupld of times. Is it crazy that she might actually be fully trained before Rhett is? I know that everyone says that boys are harder than girls, but this just seems silly. McKenna has not yet grown out of her little stage of taking her diaper off, so we have resorted to taping it on her. I feel silly doing it, until I remember just how many times I have found poop on my carpet or other fun places. :0) Oh the joys of motherhood!