I Hear Bipolar is genetic.....

....is it true?????????????

I know it's genetic, but exactly "how genetic", so to speak, is it? I know I'm young but I have an intense fear that when I grow up and become a mother my child would be bipolar like me. I don't want that, not for the sake of myself, but for the sake of the child. I would feel relentless and utter guilt, having brought someone into the world who would have to face the fears that I do. It's just not fair to put someone through that.