well, i've already

[mitch96]

11. His Mom was of Irish decent and he did not drink b/c of "the family curse"..

From a New Yorker piece on Biden:

The President considers alcoholism a kind of family curse. After growing up around hard-drinking relatives, he chose to abstain from alcohol. He also urged his siblings, and, later, his children, not to drink, although all of them eventually did—some in moderation, others to the point of addiction.

From wiki"
Of Joe Biden's sixteen great-great grandparents, ten were born in Ireland. He is descended from the Blewitts of County Mayo and the Finnegans of County Louth.