I believe that Glorious has the right of it. There is an objective moral law that says that certain behaviors are grave sins. There are also mitigating circumstances that can reduce or even eliminate culpability. The act remains grave, but the person may not be as culpable as it seems.
Certainly, many of the behaviors of addicts are driven by their illness. One can question how much freedom went into the act. This does not release the person from the original sin that cause everything else, which was abusing drugs or alcohol.
If I understand the ruling correctly, it says that those with deep seated homosexual tendencies aer disqualified from Holy Orders and Religious Life. Deep seated is not defined by the document. It's really up to the vocation director to determine what is deep seated. My interpretation of this would be:
a) a person who does not see the moral seriousness of the act
b) a person who cannot discipline himself to be celibate
c) a person who identifies himself as gay as opposed to identifying himself as a man with strengths and weaknesses
d) a person who remains involved in this culture
e) a person who has difficulty relating to both genders in a healthy manner
To say that a person has to be totally free of SSA is a little difficult, because you don't now. You have to take the person's statements at face value. But you can certainly observe these other behaviors through confession, spiritual direction, interviews, references from those who know the candidate.
I would also throw in there something that Fr. Vince Serpa recently posted. There are youngsters who are exploring their erotic feelings and engage in homosexual behavior and outgrow it. The behavior is grave, but the conditions mitigate culpability. There is a lack of maturity and probably a strong curiosity that blocks reasonable thought.
Where I'm going with this is to say that many teens have done irrational things that are objectively sinful. It reminds me of my mother's question when we messed up. "What were you thinking?" And my father would respond, "He wasn't."
Not knowing the age of the person in question, we have to factor in the possibility that this could have been behavior of an immature adolescent.
Because there are so many details that have to be discussed, there is no hard and fast answer. The Vocation Director and the Spiritual Director will have to do a lot of detective work to help the persons discern if this is where Christ is truly calling him.
Br. JR, OSF :)