J.D.
Hi G., I have 18 month old identical twin boys and they have had flip flopped behaviors (role reversals) about 3-4 times since birth. One is the sweet/sensitive one, and the other is the run right over you, get mad, and yell twin. They go back and forth every 4-5 months. I've yet to see them both with the same personality for more than a couple of days. What I do when they start getting irritated with each other and fighting over a ball for example. I will sit them both down and teach them that they can play together with the ball, and that usually works, but sometimes I will just pull out another ball from the toy box and show them that there are plenty of toys for both of them and they don't need to get upset. And when one is jealous of the other being close to me he will come over and start slapping me on the leg and growling and trying to hit his brother. So I will tell him that we do not hit, and that he needs to be sweet to brother, and so I will sit on the floor with both of them, one on each leg so that they can be close to each other and see that there is room for both of them to be close to Mommy....so far these methods are working!! Good luck!