Homosexuality
Homosexuality is when you are sexually attracted to other people of the same sex as you (and only the same sex). For example, if you are a boy and you are sexually attracted to other boys (and only other boys) you would be homosexual. Same for girls. Homosexual men? are usually called gay and homosexual women women are usually called lesbians (or also just gay).
This is probably going to be the most controversial page on this website because of what I believe. But first of all I believe that you can't choose your main sexual attraction, so it's not your fault or responsibility if you are gay and you certainly shouldn't be blamed or treated badly for it. However, I believe that having sexual activity with people of the same sex as you is wrong. I don't think God will be mad at you or condemn you for simply being attracted to people, though, and as a Christian I believe that every sin can be forgiven.
I have heard that about 1.1% of men are strictly homosexual and about 0.6-0.7% of women are strictly homosexual. So it's not that common, despite the attention in society it receives.
Some people might think they are gay because of what has turned them on (caused them sexual arousal) in internet porn. This could be you if you're a man and you seem to like transgender porn or if you're a woman and you seem to like the women in porn more than the men. (One of many reasons not to look at porn.) Most likely you're not actually gay. I should probably make an article just for this subject.
Some people have a repeated intrusive thought or fear they can't get rid of that they might be gay, and they're really not. This is called hOCD?, or homosexual OCD.
Homosexuality is called a "sexual orientation" but I currently don't use that term, partially because it doesn't explain how people can be bisexual?.
If you're attracted to both boys and girls that would mean you're bisexual, which is a little different from homosexuality.
I have heard that people have stopped being gay, but I have also heard that it's impossible to change from being gay to straight.