I think before we decide whether or not homosexuality is something that you are born with, you have to decide what the definition of homosexuality is. Some dictionaries describe a homosexual as someone who is physically attracted to someone of the same sex, while others state that the definition is someone who is emotionally attracted to someone of the same sex. Another definition even states that someone has to have physical sex with the other person in order for them to be a homosexual. I tend to prefer the psychological and emotional attraction definition more than the others.
This would mean that you are not a homosexual if you just have physical experiences with someone of the same sex, but were not actually emotionally attracted to them. This seems to happen more for females than males, where they may have a sexual experience with another female, but they would never actually date one, and in some instances (and more instances if it were up to most guys) were even with a guy they were dating at the same time.
I think in order to be bisexual, you have to be physically AND emotionally attracted to both sexes. Maybe you've dated people from both planets.
Now, if that's your definition of homosexuality, than no, I don't believe you can be born with it, nor can you be persuaded to be one way or ther other by peer pressure, parents, church groups, etc. I believe that your emotional and physical attraction to one sex or the other comes with growing up, especially during puberty where your hormones start to give you your emotional and physical sex drive. I believe that once you are homosexual or not, and you are truly attracted to one sex or the other, not just "think" you are attracted to them and you KNOW you are, then that's it. You can't be "cured." I believe some people go their whole life without even knowing that they are homosexual (or vice versa), but just know "something" is off about the way they feel.
Some people can be attracted to neither males nor females, but can have physical contact with one or both of them. Where do they fall in the church's decision. And furthermore, how can a priest even be homosexual or not being that they are not supposed to be with ANYONE?