If it helps, my 3yo is still doing pretty much the same thing your 2yo is, Ann, and we do not have bipolar issues (or any other such dignosis) in our house.
I think watching out for connections to DH's condition is smart, but I'm not 100% convinced you'll see those connections. GT kids tend to be bossy little perfectionists. If things don't go their way, they throw tantrums.
Case in point: THREE kids in an enrichment class I teach for GT kids on Saturdays threw tantrums when things in the game we were playing didn't go their way. They were 6-9yos! So being a bossy, cranky perfectionist at 2yo is sort of to be expected, I think.
I guess what I'm saying is that it may just be part of the normal development of your child. I could be wrong, so watch for signs that it's something more, but I wouldn't be too worried about it unless DS2 acts out more obviously. But what you're describing now, Ann, just sounds like a day in the life of a GT kid to me!
