My guess on Dr. Munroe: Duke's nephew, fathered by Julian Jerome! I was watching way back when Duke and Anna first met. I could swear Duke used to meet with a nun, who turned out to be his sister! Think about it, why else would Griffin and Lucas be best buds from med school? I think Griffin reminds Anna of a young Duke. I don't think she would know who his bio father is. But, I can just hear Anna now - "Jullian's got children popping up all over the place!"