[dustinzgirl]

Well-----

First, it is not uncommon for a boy to associate lust with the love of a mother, sister, ect. Yes, that may sound a little wierd, but in classical psychology it is very true. Secondly, you have to remember how inexperience Luke was, not only to his inherent power but also to the ways of the world, women and relationships. Even if he had known right away that Leigha was his sister, I think that there still would have been some underlying sexual tension based on Luke's age, unrealized desire and inexperience with 'real life' in general.