Just two comments on this thread.
1) (The following does not apply to mentaly ill individuals) It is possible for a person to change his point of bechira. An alcoholic once had bchira about drinking - though today he does not. He used his bechira to change his point of bechira and therefore though he no longer has bechira about a specific action today - he still has schar veonesh on those actions.
2) I heard from my RY over a decade ago, on the topic of same gender attraction - Klal Yisreol has a place for you. There are many postions and resposibilities that are not really possible/appropriate for a married person raising a family to do - kiruv, kashrus in far flung places ect.... so too for these people.