Any two people who marry bring some baggage with them. The two of you bring the baggage of familial mental illness. At least you should be able to understand how the mental illness of family members has affected the two of you, and maybe that will even bring you closer. Look at it not as a threat to your relationship, but one of the many commonalities you share. If you are afraid you or your girlfriend might develop a mental illness, maybe you can decide beforehand how you would handle it. If you are afraid to have children because of it -- that is a very personal decision and no one else can make it for you. Personally, if I married a loving and caring person I think the two of us could cope beautifully with a mentally ill child. You can't live your life and plan your future around things that might or might not happen, you just have to step out and live life to the fullest every day. And how better to do that than with a woman you love?
Carolyn