Rei writes:
"Would you care to list the disadvantages?"
1. With homosexuality being against God's design/plan, the people involved in such a relationship separate themselves from God. This dooms the relationship/marraige to fail from the start. In order for a relationship to be lasting/joyful/fulfilling, the participants must follow the principles given in scripture regarding their conduct and roles.
If we choose to reject God's guidelines, we inevitably create our own. Godless man's tendency is to focus on the self. The "What's in it for me?" philosophy. If we approach a relationship with that attitude, we will, as you probably already know, fail.