Isn't there a story in the bible about a son who has sex with his mother? If I recall correctly he murders his own father and then realizes it's his mother he's having sex with.
If a man sleeps with his father's wife... both him and his father's wife is to be put to death. (Leviticus 20:11)
From Wikipedia (
http://en.wikipedia.org/wiki/Incest_in_the_Bible):
The Holiness Code of Leviticus elaborates in detail the relationships it regards as incestuous unions,[4] and two chapters later specifies punishments for specific incestuous unions, but this second list of unions is much shorter than the first;[5] textual scholars regard these two lists as having originally been independent documents, bound together at a later point.[6][7][8] The Deuteronomic Code, gives a yet more simple list of forbidden relationships - just parent's daughter (including sister), father's wife (including mother), and mother-in-law.
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In Genesis 35:22, Jacob's firstborn son Reuben commits incest by sleeping with his father's concubine, Bilhah.
From the Bible, Leviticus 18:
7 "Don't violate your father by having sex with your mother. She is your mother. Don't have sex with her.
8 "Don't have sex with your father's wife. That violates your father.
9 "Don't have sex with your sister, whether she's your father's daughter or your mother's, whether she was born in the same house or elsewhere.
So to be a mother fucker, you also become cursed and violating your own father and dragging shame over yourself and disgrace to you whole family. Very, very shameful and might also result in death or to be expelled from the community.