Isn't the idea that once the couple sees their adorable baby they will reconcile?

Or contrarily, once the baby is born, and it is clear to the husband that he isn't the father, then negotiations on custody are much simpler.

You can only find out who the real father is by threatening to cut the baby in half.

Sorry. That's how you find out who the mother is. You can tell paternity by a simple blood test. That's why people talk so much about paternity testing but you hardly ever hear about testing to see who the mother is.

The Old Pretender could have used it.

Maybe it's easier to get child support. The child of a married woman is presumed to be her husband's.

6: I could see that being a motivating factor. Also, "in the process of divorce" means that the kid's not technically a bastard, right? That may have been a much worse stigma when the current set of judicial norms was established.

I think 7 is onto something. One such vestige I tripped across here in Massachusetts is that birth certificates and marriage records, nominally public records, are locked down to the immediate parties if the birth is to unwed parents or one of the people being married was born to unwed parents (because both parents of the two parties are listed on the marriage record).

I don't get all that effort to avoid the stigma of illegitimacy when regardless the stigma of Texan is going to apply.

I'd have thought the ubiquity of camera phones would make it a lot easier to prove who the mother is.

I wonder if the historical answer has something to do with presumed paternity. If they're married when the kid is born, he's the legal father. If they're not, its easier to contest it. If say it's a holdover from more patriarchal times except that would imply improvement.