As somebody who has a family member that suffers from schizophrenia, I would never want to be judged on that one fact. It is an unfortunate circumstance because its only human to feel paranoid but if you're actually feeling like this person has something to offer you and there is a genuine interest there with the person then I think you should consider that the first criteria before ruling them out due to a disease in their family. When it comes to illnesses it's a difficult dilemma because naturally you want to keep yourself, your future safe, but at the same time we can not predict what kind of illnesses will play a role in our life later and that's a hard call in my opinion. However, I married my husband even after the severe cancer history in his immediate family because at the end of the day, it was my husband I was judging not going off medical history which is such a toss up in life I think. I am one of those, everything happens for a reason types and if its meant to happen, it's meant to happen that way, theres little control over medical problems obviously and therefore not a good enough reason to not marry someone.
Speaking from my personal experience, you should not take this lightly. That "someone" with whom you are planning life time commitment, you should know him/her very well. If you suspect any abnormal behavior (you can google for common behaviors for such illnesses), then it's a red alert.
Chances would always be 50/50 that this could be inherited by kids. But you have to decide by yourself if you see more positives in that person than negatives. You have to be extremly patient person if you decide to go ahead. Whether that person is also effected or not, you should be mentally prepared for the tough times.
I am not saying that you should totally rule out that person as potential spouse, but you have to be careful and satisfied enough to take any further step.
bipolar is very hard to cope up with , it has many drawbacks , patience suffering from these illnesses are difficult to be around with especially in a relationship so , unless you are completely in love with the guy , do not marry him