How and when was homosexual practice separated from "homosexuality"? Many of the recent denominational statements on the topic of human sexuality make a clear distinction between being aware of having same-sex attractions, and engaging in same-sex erotic activity.  Examples:


The 1980 statement of the American Lutheran Church said,


  We believe it appropriate to distinguish between homosexual orientation and homosexual behavior. Persons who do not practice
  their homosexual erotic preference do not violate our understanding
  of Christian sexual behavior.
  The early draft of the 1993 version of the Catechism of the Catholic
  Church said,
  "Homosexuals do not choose their condition. For most
  of them it is an ordeal."
  
  In contrast, it is not too hard to find on the web condemnations of "homosexuality". As in condemnations of having the orientation.  The point of contention between the two camps is what is to be said of the celibate homosexual: do they exist? do they need to achieve "orientational conversion"?


So my question, for those who agree that there is a distinction, is how and when did such a distinction come about? Can it be found in treatments of the church fathers?  Or is it a relatively modern distinction, coming about after seeing homosexuals in the community?
In Catholic teaching, I believe the distinction was always there, although I am sure the idea of what sexual orientation actually is has developed along with our understanding of the subject in general

Like the distinction between instinctive lust/desire and indulging in it mentally or physically, so the distinction with homosexual attraction and indulging in it. 

The catechism draft you quote (I have no idea how authentic it is, but that's not important) does not really shed any light on this question - A person may not choose to have homosexual attractions, anymore than a person chooses lustful attractions. This does not mean that the sexual orientation is born-in. In fact, from my lay-person-intensive analysis of the literature of the subject, we are pretty certain that sexual orientation, although biology plays a part, is not fully (max 50%) determined by biology. 

SIDE NOTE pornography shows us "nicely" how malleable our sexual orientation is. the kind of things that a person can be conditioned to get turned on by, would scare the crap out of them before they get into it.