Nature vs. Nurture
The quote I posted from Desmond Tutu created discussion concerning over whether homosexuality comes from the genes or our social environment. But there is no consensus with the relevant sciences.
It seems likely that it's a mixture, but however that gets worked out, few think it's a volitional choice. But that in itself wouldn't solve the debate about whether we're talking about moral behavior or not. All it can tell us is it's origins and that's about it.
And orientation does not indicate whether one has a moral relation or not. We have to examine particular relationships whether they build up love, mutuality, commitment, the development of moral possibilities among those in the relationship.
One can find examples in both orientations where this is the case. And we can find broken, destructive relationships in both orientations as well. The church's business is to build up the prior. And because we're not doing that we've lost moral authority on sexual matters. That's a shame and it needs to change.