I've done a lot of personal thinking about whether pedophilia can be considered a sexual orientation. I think what has to be recognized is that there is both a biological and social construct aspect to that question. That is to say, the whole notion of orientation is a relatively recent one. I'm not just talking about impulse vs. action, but rather how a mind -- raised in a certain society -- processes and internally articulates impulses. Its very hard for people inside one society to step out and see how any other society could ever see any thing different, but its necessary to get proper definitions of these things.
In most patriarchal societies, traditionally sex has been tied to power dynamics and the "orientations" they would have been able to discuss would not have been hetero vs. homosexual but rather dominant vs. passive (do you desire to be in control or do you submit to being controlled?). Age, gender, or any other attribute would have been secondary to that distinction. The normative sexuality was for adult males to be in the active role and every other segment of society to be in the passive role. Everything existed within a power hierarchy. It was not until the more obvious hierarchies started breaking down (through the reformation, age of enlightenment, and political revolutions), that people began to recognize that there were other ways of defining their sexuality other than through power differentials.
So as power and sex began to become less linked, the driving question in sexuality orientation began to be less about "are you in control?" to "who are you attracted to as an equal?" This is an ongoing and unfinished change in human society, but the question itself does provide useful limits. People can and do still say "I find being in control sexy," but no one is going to call that urge an "orientation." For most of human society, it was assumed that the desire to be intimate and the desire to dominate were linked. Now we reject that notion. Thus, pedophilia cannot be an orientation in the modern sense of the term because it is about being attracted to a power differential rather than being attracted to an individual.
The other side would argue that pedophilia is an orientation because the pedophile has a deep sexual desire that was not chosen, cannot be changed, and that the impulse remains whether or not it is acted on. That argument ignores the fact that pedophilia, acted on or not, is not a desire for equal companionship but rather a desire for domination. The doctor in the article argues that there is a range of "feelings" that the pedophile has and they are not always violent or desiring obvious overt domination. But the pedophile is not attracted to the person, but rather a superficial and changing aspect of the person. But so what? Many one night stands are completely erotic affairs based on fleeting beauty. The difference is that the sexual pathology that leads consenting adults to make sexual decisions based on superficial features is not universal to either homosexual or heterosexual orientations -- and in fact the shallow experience can be a door that leads to a more deeper mutual relationship. Healthy sexual attraction often becomes a motivating factor toward a mutual relationship based on the individual essence of the two involved. But at the deepest level, a pedophile cannot be longing for a permanent mutual relationship with an individual. Age is transient and not only is mutuality impossible, there is nothing in the child's personality that would suggest otherwise without the pedophile deluding himself. Self-delusion is not a characteristic of a healthy sexual orientation.
True sexual orientation asks "when selecting a mate, which gender do you prefer as the initial step toward paring the available population down to a specific individual in which to conduct an egalitarian courtship with?" It includes transient physical characteristics but anchors in the hope of a deeper alliance. Pedophilia cannot answer that question because the attraction is based on an entirely superficial level and any deeper relationship formed would be based on power (even if it is subtle rather than violent) rather than equality.
So if pedophilia is not an orientation, how do we define the unchangeable, erotic impulses? I don't see how this question is any different than defining the impulses of those who cannot become aroused without murder or violence. We don't call sado-sexual homicide (or the desire for it) an orientation. It is a pathological desire. Orientation in a person begins broadly, but eventually narrows down to connecting with the individual as a real meaningful being. Pathological desires never lock on to the individual as an individual but forever remains in the realm of "what can that individual do for me?" It is an utterly different view of sexuality and an ultimately crucial distinction in recognizing that sexual orientation is a question of "who am I attracted to," but pathologies like pedophilia are a question of "what can this person do for me?" Obviously such narcissistic dysfunction can and too often does exist inside both homosexual and heterosexual adult relationships, but pedophilia (action OR impulse) cannot exist without this dysfunction. Therefore, pedophilia is truly defined by this aspect of it and therefore does not fit in anyway under an reasonable definition of orientation.
"it's good to be young but let's not kid ourselves -- it's better to pass on through those years and come out the other side with our hearts still beating;
having stared down demons and come back breathing." -- John Darnielle