It's generally for people with children I think.

(moomin-papa ; folkin class., Tue 15 Nov 2005, 1:09, archived)

I didn't know you were a dad.

( Randomgazz, Tue 15 Nov 2005, 1:10, archived)

I have several children,
about 3 per wife on average.
(moomin-papa ; folkin class., Tue 15 Nov 2005, 1:13, archived)