Peter is Mary's biological father.
The plot reveals that Peter is Mary's biological father, though initially believed to be Jack.
Jack acts as Mary's guardian and co-parent.
Jack initially believes he is Mary's father based on Sylvia's note, and later becomes a co-guardian.
Michael is a co-guardian to Mary.
Michael helps care for Mary and becomes a devoted co-guardian.
Explore the full interactive character relationship map of 3 Men and a Baby