Infanticide has been a part of many cultures and children seen as deformed or unlikely to survive would be left to die of exposure. It was a fact of life that no one need like, but it was done as there was no real alternative. The series Vikings had an episode where Ragnar takes his crippled infant son out to leave him, but has second thoughts and brings him back.

The weak were rarely permitted to drain the resources of the family. In the scenario you describe, such tainted children could be seen as potential connections to a darker god and a danger to all.

In Zelanzny’s This Immortal, the protagonist was left to die because of the day on which he was born, which according to his culture made him dangerous. Not all infants left to die do as others sometimes encounter them and adopt them - Oedipus for example.

Show the parents fear of the infant and fear for the harsh life he or she would have if left to live. A potential threat to society and marginalized - essentially a leper. It could be seen as a desperate act of love - ‘Can’t let this sweet babe suffer, so goodbye and better luck next time’ and then the parent kills the child to prevent his future suffering.

The doctor or whoever examined the infant to determine if they are worthy of life can be shown to dislike this aspect of life, but understand that preventing pain is a good thing. Living on the margins, looking like some kind of demon, the child was damned from the start.

Statistics showing the propensity for such a child to go dark - because of ostracism - would be given and mention of some of the more dangerous among them whose parents had hidden them away rather than do the responsible thing. Society demands what it demands.

In China, under the one child rule, many daughters were left to die so the parents could have a son to pass on the family nane. Such sons had difficulty finding wives as many hadn’t been allowed to live.

Life can be dark and almost anything can have a reason or rationalization. Make it necessary and the reader will accept it.

Infanticide has been a part of many cultures and children seen as deformed or unlikely to survive would be left to die of exposure. It was a fact of life that no one need like, but it was done as there was no real alternative. The series Vikings had an episode where Ragnar takes his crippled infant son out to leave him, but has second thoughts and brings him back.

The weak were rarely permitted to drain the resources of the family. In the scenario you describe, such tainted children could be seen as potential connections to a darker god and a danger to all.

In Zelanzny’s This Immortal, the protagonist was left to die because of the day on which he was born, which according to his culture made him dangerous. Not all infants left to die do as others sometimes encounter them and adopt them - Oedipus for example.

Show the parents fear of the infant and fear for the harsh life he or she would have if left to live. A potential threat to society and marginalized - essentially a leper. It could be seen as a desperate act of love - ‘Can’t let this sweet babe suffer, so goodbye and better luck next time’ and then the parent kills the child to prevent his future suffering.

The doctor or whoever examined the infant to determine if they are worthy of life can be shown to dislike this aspect of life, but understand that preventing pain is a good thing. Living on the margins, looking like some kind of demon, the child was damned from the start.

Statistics showing the propensity for such a child to go dark - because of ostracism - would be given and mention of some of the more dangerous among them whose parents had hidden them away rather than do the responsible thing. Society demands what it demands.

In China, under the one child rule, many daughters were left to die so the parents could have a son to pass on the family name. Such sons had difficulty finding wives as many hadn’t been allowed to live.

Life can be dark and almost anything can have a reason or rationalization. Make it necessary and the reader will accept it.