Roman exposure

The Romans, perhaps ashamed of their past, abhorred human sacrifice. According to this, burying unchaste Vestals and drowning hermaphrodite children wasn't human sacrifice—and it probably wasn't. The one was punishment for a criminal offense, a danger to the city, and the second was probably also a public safety measure (it looks human but isn't?).

But they exposed unwanted children. I was curious how the death rate from that compared with that of the explicit child sacrifice among the despised Carthaginians. Short answer: no numbers.

Rabbit hole: Exposure killed a lot of kids, but some survived and what became of them was complicated. How the child was exposed mattered--some were put where they would be quickly found, and some even had identifying trinkets--and some Roman plays involved reconnection with the original parents. But contemporary writers assumed that many would die.

The finder wasn't supposed to make a slave of a free-born baby, but in practice babies were often raised as slaves or prostitutes.

The second link is about the legal status of the children, under Roman, Jewish, and Christian rules. I'd forgotten the bit about "slaves abandoned because they were sick automatically became Roman citizens"--Claudius had some good ideas.

As you probably guessed, with the rise of Christianity, Christians rescued the exposed children they could find, and after it became lawful to have churches, those became places to leave the babies.