re: #58 darthstar
I have no idea where Christians get this notion. There certainly are prohibitions against “Onanism” but Jewish commentators all agree that the punishment for Onan was due to his disobeying G-d’s command. Adultery is a much more serious offense. In any event, one is never accountable for thoughts, only for actions.
(Similarly, if you read even a traditional Orthodox commentary on the story of Sodom, it will stress that the sin of Sodom was inhospitality, and being cruel to a stranger or visitor.)