Who? When? How?

Suppose you are asked to define first-time fatherhood. Do you offer a single definition?

Is Red Hot Chili Peppers frontman Anthony Kiedis a dad just because girlfriend Heather Christie gave birth to a son sharing his DNA? Could four-time father Kevin Federline be defined as a new father, now that he seems to be taking the role seriously? Or are you a (re)new(ed) dad every time you face another step in your child's life, from when s/he is born to when they get on the school bus alone to when they ship you off to the home.

Or should you think of "fatherhood" as Justice Potter Stewart explained obscenity: something he knew when he saw?

** But the usual elements are? **