Yes, just like the thoughts you have when you see a good-looking guy on TV, a lustful thought is sinful.<quoted text>
And the thought is not?
Really, you tell your kids hating their brother in their heart is not a sin but the act of murder is the sin?
That would still make them a murderer by using your logic.
Marge, do you think a homosexual person who has homosexual thought is more sinful than your adulterous thought?