Kalel, you're right that if one parent is bipolar, the odds are 30% that the child will have it. But if both parents are bipolar, the odds shoot to 50-75%, making it very likely that the child will be affected. If you've ever had any experience with mental illness, I'm not sure I'd say that bipolar is "better" than sickle cell or Huntingtons. Mortality is 25% for bipolar, and lots of suffering to the rest. Anyway, it's a touchy subject with no real right answer. Many people who know they have Huntingtons or sickle cell choose not to have their own children also. I guess it depends on what the parents are willing to live with and work at.