Our behavior, whatever that behavior is is determined by several things.
*Our environment
*Who we associate with
*Our own values and morals we develop over time
All of these things are linked to our own minds. The mind is the most powerful tool we have, it can talk us into or out of anything in this world. It can justify any behavior we desire it to.
There is no homosexual gene, same is there is no heterosexual gene. The fact remains, human beings are designed for relationships with members of the opposite sex. Pure biological function tells us this. We can become enthralled with the opposite of this, simply by terms created by the three things I listed above.
It has nothing to do with "Why would anyone want to be gay?" When the human mind begins to desire something, when it desires it enough, the negative aspects that may follow mean nothing...people will want what they want regardless.
But simply wanting something does not make it right. Simply saying it's my choice, does not make it a good one or the right one. And all societies are affected by what everyone in the society does. Even in a free country we are not free to do 100% as we please. If this were the case I would be shooting people on a daily basis, lol!