SMOGZINN
Lifer
And to some extent, it's easier to prove children born within a marriage are those of the father (it's generally presumed), so legitimacy does matter in some situations.
This is something I have some knowledge about. Parentage is not presumed, it must be on the birth certificate. A new mother can name anyone she wants as the father of her child on the birth certificate, regardless of marriage. It is then up to the presumed father to prove otherwise.