Does jewish life begin at conception, birth or brit milah (for baby boys) or even later than that?
You’re actually asking two separate questions – as the others have mentioned, Jews believe that life begins at first breath (when the head is born), or in the case of a breach birth, when the majority of the baby’s body is delivered. Up until that point, the baby/fetus is considered as having the potential for life, but is not considered a separate living being. It’s treated more like a limb of the mother – if he life is in danger, the limb must be sacrificed to save her. But the question of when the neshama arrives is open for debate. There is a differentiation in Judaism between a newly conceived fetus and a fetus that has reached 40 days (roughly when the heart starts to beat) – before the 40-day mark, the fetus has even less status as a potential living being than afterwards, so it is possible that there are people that believe that that is when the baby’s neshama arrives. Other sources mark a differentiation at quickening (roughly 18-24 weeks, when the mother can feel movements).