[HarleyD]

The disposition in itself is not sin. It may lead to it; then it may not.

Sorry, I'm not buying.

Mat 5:28 But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart.

Our Lord states that if you "looked on a woman to lust" you've sinned the sin of adultery. You don't have to do any overt action. All you have to do is do it in your heart. James emphasizes this view when he states, "Jam 1:15 Then when lust has conceived,". Once lust is conceived, it can't be aborted. Sin is sin whether by action or by thought.

[annalex]

You are spinning the word "lust". Predisposition -- sexuality -- is not yet lust. Lust is a decision. Thus understood, it is indeed sin (except maritally).