In an effort to normalise homosexuality, LGBT advocates often appeal to genetics. Homosexuality, they argue, can't be wrong, because it is as natural a trait as skin color. This is why "homophobia", whether real or imagined, is sometimes compared to racism.
But the thing about gay people is they can only reproduce by breaking their homosexual habits. A man cannot reproduce with another man, nor can a woman reproduce with another woman. I shall spare you the high school lesson on exactly why, but needless to say, only a man and a woman can work together as what the Bible calls "one flesh" in order to produce a baby. The baby then inherits traits from both his/her mother and father.
In nature, there is a phenomenon known as "natural selection". Traits that provide an advantage to reproduction are typically passed on to the next generation. Traits which hinder survival or reproduction, by contrast, only last a few generations, if that. The result of this is that only beneficial or neutral traits stand the test of time. Homosexuality, of course, is a hindrance to reproduction, which should lead to a decrease in homosexuality as gay people live out their lives, having never reproduced, and ultimately die like the rest of us.
If homosexuality was a genetic trait, natural selection would eliminate it quickly, within one or two generations (assuming some gay people break their habit and do reproduce). Natural selection is having no effect on homosexuality. In fact, it seems to be increasing dramatically. Therefore, there must be something else at play in order for homosexuality to have persisted for as long as it has.
That something else is called sin. Sin is that which we do in rebellion to God. It is not limited to homosexuality, but homosexuality is included in it. Unfortunately, every single human being has rebelled against God in some form or other. I, myself, am an ex-gay, which means homosexuality is on my long list of sins. For this rebellion, God offers only one penalty: Death.
But the good news for sinners like me is that God does not just leave it at that. Death is the penalty for sin, but praise be to God, it does not have to be the sinner who receives it. Around 2,000 years ago, God sent His Son, Jesus, to be born of a virgin, live a perfect life, and die on a cross at the hands of sinners. Jesus then spent 3 days in a tomb before rising again. Through this, Jesus guarantees eternal life to everyone, regardless of their sins, who will repent and believe in Him. This is something you were born to do.