In our modern world, homosexuality is an issue close to everyone's hearts. On the one hand, you have those who cherish it, who celebrate it, and will call you all sorts of horrible names like "homophobic" and "bigoted" if you so much as hint that perhaps you might disapprove. On the other hand, you have genuinely homophobic bigots who are so full of hate, they would disown their own children if they came out as gay. Of course, Biblically speaking, homosexuality is wrong. But is it ok for a Christian parent to to disown their gay child?
The short answer to this is no. In fact, the person who asked me this question made a very important point: It is inconsistent to do so. Sin is sin, and homosexuality is not a special one. There are a number of sexually immoral things a straight person can do, and yet these very rarely result in being disowned. Not only that, but although sexual immorality is seen as a "special" sin in that it is done against your own body, it is not a special sin in the way God deals with it.
See, in God's eyes, sin is sin. Even if you are absolutely perfect in all other ways, but you sin just once, God says you've broken the whole law (James 2:10). Ever lusted after a woman? You're as much of a sinner as a gay person. Ever lied? You're as much of a sinner as a gay person. Ever made a genuinely homophobic comment? You are as much of a sinner as a gay person.
To be sure, there are cases in which the Church should disfellowship certain sinners. In 1 Corinthians 5, for example, Paul addressed the Corinthians regarding an incestuous relationship between a son and his mother. In verse 5, Paul says "deliver such a one to Satan for the destruction of the flesh, that his spirit may be saved in the day of the Lord Jesus." But this is not the same as a parent disowning their child. Rather, it is an individual congregation leaving a sinner to their sin, allowing the sin itself to destroy the one committing it until they repent. Notice that Satan is the one who shall destroy the sinner's flesh, not the Church, and not the parents.
Matthew 18:15-17 sets out guidance for dealing with an individual sinner. First, a personal rebuke (which, it should be noted, should not come from someone dealing with the same sin, as per Matthew 7:1-5). If the sinner will not hear that rebuke, two witnesses should be brought to rebuke them a second time. If the sinner still will not repent, the Church should be informed. Jesus' final command? "But if he refuses even to hear the church, let him be to you like a heathen and a tax collector."
But how should a heathen and a tax collector be treated? Notice that there is not one place in the entire Bible that permits the abuse or mistreatment of heathens. The Bible is absolutely flooded with commands to love your enemies (Matthew 5:44), live at peace with all men (Romans 12:18) and pray for those who persecute you (Matthew 5:44 again). Even those LGBT advocates who are currently running around suing Christian businesses for refusing to cater to gay "weddings".
See, although they misuse the term, there is one thing the LGBT movement has right: It does all come down to love. John tells us in 1 John 4:8 that if we do not know love, we do not know God. Why? Because God is love. If you don't know love, you don't know God, so how can you know God if you don't love your own children?
The definitive passage on understanding love is 1 Corinthians 13:1-7. It says "Though I speak with the tongues of men and of angels, but have not love, I have become sounding brass or a clanging cymbal. And though I have the gift of prophecy, and understand all mysteries and all knowledge, and though I have all faith, so that I could remove mountains, but have not love, I am nothing. And though I bestow all my goods to feed the poor, and though I give my body to be burned, but have not love, it profits me nothing. Love suffers long and is kind; love does not envy; love does not parade itself, is not puffed up; does not behave rudely, does not seek its own, is not provoked, thinks no evil; does not rejoice in iniquity, but rejoices in the truth; bears all things, believes all things, hopes all things, endures all things."
That is a lot to unpack, so much so that I don't intend to go into too much depth in this particular article. But most relevant here is that although love does not rejoice in iniquity, it is also longsuffering, kind, rejoices in the truth, and bears all things. It is not loving to celebrate homosexuality, as the world does, for that would be rejoicing in iniquity. But it is also not loving to persecute those who do. In fact, a good rule of thumb is to ask yourself two questions: 1. could God legitimately treat me this way, and 2. would I be happy if He did?
The answer to the first question is always going to be yes. God can have mercy, and God can reveal His wrath. The penitent sinner can benefit from the former, and all sinners who refuse to repent will receive His wrath. You fall under one of those categories. There is no third.
The answer to the second question is slightly more difficult. Obviously, no one is happy with a solid rebuke when it first comes. But in the long run, while discipline is good, homophobia is not. Would you be happy if God disciplines you? In the long run, yes, but ultimately, you want mercy. If God disciplines you, you want it to be with your good in mind. If God disowned you, you certainly wouldn't be happy. That is the literal definition of Hell. So, go for the Golden Rule: Do unto others as you would have them do to you. Straight, gay, it doesn't matter. God's greatest commands are to love Him, and to love our neighbours. If you don't know love, especially if you cannot love your own family, you don't know God.