Leviticus 12 is interesting because of a link with the New Testament. It gives the rules for a woman's purification after childbirth. She has to bring a sacrifice of atonement for her 'uncleanness'. It should be a lamb and a pigeon or turtledove, but if she cannot afford a lamb she can bring two pigeons or turtledoves.
In Luke 2:24 we read that after the birth of Jesus Mary and Joseph went to the temple for her purification, taking 'a pair of turtle-doves or two young pigeons'. This indicates that they were relatively poor - a point often made in sermons.
But this raises at least two questions. First, why should a woman have to make a sacrifice to 'atone' for having given birth to a child? And secondly, how does this fit in with the Roman Catholic idea of the immaculate conception and perpetual virginity of Mary? Why did she, of all women, need to be purified?