Q. Is it okay for Christian boys to call each other names like "homo" or "retard"?
A. Name-calling terms, such as "retard" or "homo" aren't Biblically permissive to call another person. One is in regards to a sexually perverse lifestyle and the other is making fun of a birth defect.
Philippians 2:3 - "Do nothing from selfishness or empty conceit, but with humility of mind let each of you regard one another as more important than himself."
James 3:17-18 - "For where jealousy and selfish ambition exist, there is disorder and every evil thing. But the wisdom from above is first pure, then peaceable, reasonable, full of mercy and good fruits, unwavering, without hypocrisy. And the seed whose fruit is righteousness is sown in peace by those who make peace."
One could argue that these terms are being used figuratively, rather than literally. No matter how LITERAL you are being in such name-calling, it is still not Biblically permissible.
Also, as Proverbs 22:15 says, "Foolishness is bound up in the heart of a child, but the rod of discipline will drive it far from him." As parents, we are to be encouraging our children to become disciplined in the ways of Jesus, not in the ways of their peers and other foolish thinkers. Discipline in someone's life does not come naturally, when they come of age. Rather, it is something that is taught to someone and practiced until it becomes a part of who they are.
One more passage to consider is Ephesians 5:4 "...and there must be no filthiness and silly talk, or coarse jesting, which are not fitting, but rather giving of thanks."
All that name-calling is foolish talk and is not suitable for those who are to be being trained in how to be a godly young man. I love Ephesians 5! It instructs Believers on how we are to be as children of God. This is a beautiful passage after which to pattern one's life.
Consider your talk momentarily. Does your language represent Christ? Are you teaching your children to become disciplined in their speech?