In Once Upon A Time in America Noodles’s gang switch around a lot of babies in a maternity ward, (lets say 100 of the purpose of this OP). They then “lose” the information of which baby is which. If this really happened, 100 newborn babies (50 girls, 50 boys) with the same skin colour randomly switched around, how accurately do you think they could be reassigned without DNA?
Lets say it was impossible,you were the parent and you know that each baby had a 2% of being yours, with no likelihood of ever finding out for sure. Would you still want to take one?
As I read it, the OP asked two very different questions.
With 1930s tech, how accurately can we unscramble the babies? Or equivalently, how many Moms can be reunited with the right baby? is the answer a few, many, most, all? And how is the unscrambling trick to be performed?
Folks upthread have tried to address that and I have no input on that one.
Nobody has touched the second question so far. And it's the more interesting one to me:
Assuming we do not unscramble them at all so each Mom will simply be handed a baby at random, how many Moms will knowingly choose to take the random baby they’re offered vs choose to go home empty-handed? There is no third choice: it’s random or none; take it or leave it.
Now that is a wild question.
The Moms will be in the full flight of hormonal arousal for baby bonding. But fully consciously aware they’re being handed some random infant almost certainly unrelated to them. And probably still pretty wiped out from the considerable effort of childbirth.
I suggest the answer will strongly depend on how soon after birth the offer is made. And will hugely vary across Mom personalities, the era and culture, and family circumstances. e.g. single parents, 1st borns, 5th child, etc., are all variables in the mix. And whether Dads get a vote in the decision. Although how the Dads’ collective answers would differ from the Moms’ is another fascinating topic for speculation. Another one, in an era where the fetus’ sex is known in advance, is how the sex of the fetus vs the sex of the offered baby affects the decision. There’s also a big cultural input to that tradeoff.
Foster and adoptive parents attach to non-bio kids pretty readily. Going home empty-handed seems a lot like voluntarily choosing the same devastation that follows a still-birth. IOW, that will be a very rare choice.
And of course in the real world there’s no chance all 50 of the 50 Moms are just meekly accepting this cruel lottery. Instead there’s going to be hell to pay. Everything we know about Nature says separating mammalian mothers from offspring doesn’t go down smoothly or easily.
But it’s all fun to think about as long as we accept we’re talking about spherical cows.