I am a totally straight female. I identify myself as a Christian. I believe what Jesus had to teach us of kindness, charity and love. Jesus modeled for us what I believe to be the best approach, when he made friends with, and even chose some of his disciples from among the ostrasized and reviled members of the society in which he lived.
It does not bother me in the least, nor do I feel it is any of my business who ANY adult has sex with, as long as it is consensual. The only time it may BECOME my business is if my partner is cheating on me.
Of the gay and lesbian people I personally know, every one of them knew they were "different" from others of their gender as very young children.
I have watched infants grow to adulthood, and subsequently come out to me and others as gay or bi. It seems pretty obvious to me that sexual orientation is present at birth. I am unaware of any scientific studies that show a genetic componant, but I also don't know if anyone has ever studied that.
As a straight female, I never had to DECIDE to be attracted to males. I just AM, and I always have been. I have female friends that I love, but I am NEVER sexually attracted to them. The thought of myself being sexual with another female is personally repugnant to me, but it obviously is not the same for lesbians.
I assume the same situation applies to everyone. We don't DECIDE, or CHOOSE who we are attracted to for friendship, for love, OR for sex. We all make choices to act on our feelings in certain ways, but the feelings of attraction themselves are NOT A CHOICE.
I pray that we can get beyond worrying about all that and see each other as individuals, all created by the same God, with worth as human beings.
The very idea that some people think it is their personal business who other people have sex with, seems like the very problem or a sickness to me. It is voyeurism and purient interest in something that is none of their business. That strikes me as very inappropriate, unless you are sexually involved with one of the parties yourself. It is NOT sick, sinful or evil to have sexual attractions. That is how we are made.
The only places I believe society has a valid interest in sexual behavior is when it is not consensual, as in rape. In the case of children, animals, vulnerable adults, etc., they need to be protected and defended from sexual preditors. Consensual sex involving adults should not be society's business.
If you are straight, gay, bi, transgender or whatever, and you are not sexually attracted to someone, DON'T have sex with that person. Quit worrying about what other people do. Be true to yourself.
It seems pretty simple to me.