I would prefer the unproven if the proven had any bipolar illness in her family.
This is one reason we did not proceed with another donor in July of this year - I saw family pictures and they haunted me; I sensed mental disorder in the family.
My sister is bipolar and my father was as well. There is nothing anyone can really do about bipolar illness (despite what people say), and their illness set our family up for incredible pain. To this day, my sister, who is nearly 50 is mean, angry, disruptive and uses everyone in our extended family for money. My father simply could not hold down a job and had a terrible temper at times he had no control of, which scarred us all (though I loved him dearly). Thank goodness, my sister no longer speaks to me (she won't tell anyone why, and I am now thankful she does not speak to me, as she traumatized me too much with her swings).
If you do have a child with bipolar disease, you may end up managing their troubles for the rest of your life, and worrying that they may be homeless or not taken care of after you die. This is the case with my mother. She is fighting advanced cancer and my sister's disease still took priority many times.
Using DE for me, this is the greatest hope of all, that there will be little chance of this occurring in our family.