I wonder if beliefs like the following could explain Israel's comfort with killing children?
Rav Yosef says: Come and hear a resolution from a mishna (Nidda 44b): A girl who is three years and one day old whose father arranged her betrothal is betrothed with intercourse, as the legal status of intercourse with her is that of full-fledged intercourse. And in a case where the childless husband of a girl who is three years and one day old dies, if his brother, the yavam, engages in intercourse with her, he acquires her as his wife; and if she is married, a man other than her husband is liable for engaging in intercourse with her due to the prohibition of intercourse with a married woman. - Sanhedrin 55B