Question
Why do a leper and a woman who has given birth have to bring a sin offering?
Answer
The sages say that "leprosy" is a consequence of slanderous speech; this is a spiritual cause, not a medical cause, and it may explain why a leper must bring a sin-offering, since slander is a sin. The sages also say that a woman in labor will almost certainly swear never to have sex again, and since this oath will almost certainly not be kept, she brings a sin-offering because of the "false oath" — not because childbearing is in any sense a sin.