I have read in a couple of places that the chance that children with one bipolar parent will also be bipolar is about 25%. At least you know very well what the signs are that you need to watch out for. Good luck.
My mother, grandmother and Aunt all had the same type of Bipolar that I do. It is very strong in our family history. My 17yr old suffers with depression and agitation so I'm watching her closely. I want to make sure she just isn't going through some of the normal teenage behaviors but I think she might have bipolar. I'm just observing her for now, it's very mild.