I think it's important you stress *sexually* attracted. As a single guy in my early 40s I don't expect that I'll ever become a father (not that I'm ruling it out I think just the odds are now against me) sometimes I see a father/son together showering in the locker room, or playing basketball on the court, etc. and I have attraction- social attraction- but it's based upon the joy I feel by recognizing how lucky the boy is to have a strong father role model -and a bit of selfish longing for what I won't have in my life--- to see it out in public appropriately modeled to others is awesome.
Sometimes I'm attracted to the beauty of youth - teenagers of both sexes- WHO ISN'T??? but hey folks that doesn't mean I'm a pedo. That means I recognize beauty, charm, intelligence... Acting puts fire under intent- and I hope people realize that passing thoughts don't mean you're wierd- it's actions and behavior that dictate whether you are inappropriate in any situation. At that point, the law is actually very freeing (remembering 'jailbait') because it provides a great envelope of protection- keeping you steered well away from danger. Part of being mature is learning to be responsible for your passing baser impulses, and showing self control and restraint. Otherwise, why not just grab a club and go out and find a mate to drag home by his/her hair like the caveman days?
Again I think the sad part is that it's nurture that helps to inform proper guidance and socialization, and helps keep young boys and girls out of trouble. Societal influences, pop culture and the internet all conspire to make it extremely difficult to keep a nuclear family together, and keep a young dude from feeling isolated, misunderstood, and alone. As men it's all of our jobs to watch out for the little dudes in danger, and set a great example for the next generation to follow.