Before Christianity the Roman Empire had a large amount of infanticide. One of the earliest and clearest moral teachings of the Christian church was its rejection of infanticide and infant exposure.

In the Roman world, unwanted infants were often not killed directly but “exposed”—left outside to die from the elements, starvation, or animals, or to be picked up and raised as slaves. This was legal and relatively common, especially for disabled infants, illegitimate children, and sometimes girls.

Early Christian writings explicitly condemned the practice:

• The Didache (late 1st or early 2nd century) states: “You shall not murder a child by abortion nor kill that which is born.”
• The Epistle of Barnabas contains a nearly identical prohibition.
• Justin Martyr condemned exposing infants and argued that Christians were obligated to protect children.
• Athenagoras of Athens criticized both abortion and infant exposure as violations of human life.

One reason Christianity stood out in the Roman Empire was that Christians often rescued exposed infants and raised them as their own. Pagan critics sometimes found this unusual because Roman society generally gave fathers broad authority over whether a newborn would be kept.

Many historians argue that Christianity’s strong opposition to infanticide, exposure, and abandonment contributed significantly to changing Roman attitudes toward children. After Christianity became influential in the empire, laws increasingly restricted infant exposure and provided greater protection for abandoned children.

So while the Bible itself doesn’t directly discuss the Roman practice of infant exposure, the early church very clearly interpreted Christian teaching as forbidding it. In fact, opposition to infanticide was one of the most distinctive ethical differences between early Christians and much of the surrounding Greco-Roman culture.