I accept that, in the same way that a recovering alcoholic, will always be an alcoholic, that a homosexual inclination may be permanent. I am not a big fan of ministries that try to "fix" homosexuals and encourage them to marry someone of the opposite sex. This is completely unfair to both the homosexually inclined person and the spouse. On the other hand, I have known people who have changed their behavior from that of a practicing homosexual to that of a practicing heterosexual, even without any sort of coercion from the Church. I am in no place to judge whether they ever were truly homosexual or if they are now heterosexual (in terms of inclination) or if they were always latently bisexual. Another point is that the Bible teaches that "Nothing is impossible with God." Therefore, I do not put the changing of one's "orientation" in the realm of the "impossible." I would accept, however, that on one's own strength it is impossible, in the same way that it is generally regarded as impossible for an alcoholic to recover on his/her own strength. I would also accept that, for the most part, the more viable solution for many gay Christians is practice a life of celibacy. And, in these cases, the mission of the Church in working with such people is to help them to discover ways to enjoy personal intimacy with other people in a non-sexual way.
As for this being and "valid orientation given by God," I'm afraid I will have to disagree with you. I believe many of us have inclinations that are the result of various experiences that we have faced during childhood and such. Some of these cause us to deal with temptations that others may not struggle with. Some of these inclinations may be as benign as music preferences, hobbies, etc. I see homosexuality as in the former category, not something inflicted (or given) by God.
Finally, I won't comment much on the comment that homosexuality is practiced by animals, other than to say that you are valued so much more than are the animals, so there is no reason to compare yourself to them.