[SoothingDave]

Based upon my reading of the passage from Leviticus, I don't think it even applies to the infant. It says "one burnt offering and one sin offering ... for her" -- meaning the mother.

What is the sin?

SD

[malakhi]

What is the sin?

Leviticus distinguishes between "sin offerings" and "guilt offerings". I don't think you can read "sin", here, in the ordinary sense.