I've heard the term "illegitimate children" all my life. Many times from church goin folk.
I guess if that were the case, then Joseph made an honest woman out of Mary, by marrying her, and adopting her "illigitiment baby".
My point is, before anybody gets their panties in a wad is. I don't believe there has ever been in the history of the planet, an illigitiment baby born. But there have damn sure been a bunch of "illigitiment parents".