We believe that individuals are the ones that can best make decision on what is best for the fabric of society, especially surrounding such private things as who and how many people can or cannot 'legally marry'. We believe the more diversity the better, and to the degree that people are enabled to get what it is they each most want, the better society will be. Outside of primitive and faithless interpretations of scripture, we believe most all rational evidence and arguments point in this direction.
We hope others will help concisely enumerate such arguments and evidences.