Punishment: Death Penalty for Incest
Source: Nav
Leviticus 20:11, 12, 14
If a man lies with his father’s wife, he has uncovered his father’s nakedness. Both must surely be put to death; their blood is upon them. / If a man lies with his daughter-in-law, both must surely be put to death. They have acted perversely; their blood is upon them. / If a man marries both a woman and her mother, it is depraved. Both he and they must be burned in the fire, so that there will be no depravity among you.