Alright, fine. If we assume for the moment that homosexuality is a 'learned trait' or caused by 'social pressures' or somesuch, then 'society' is responsible for creating homosexuals. If society is responsible for creating homosexuals, then society cannot condemn homosexuals else it condemns itself for creating homosexuality. If society is unwilling to condemn itself for causing the creation of homosexuals, then it cannot condemn homosexuals. If it cannot condemn homosexuals, then it cannot legally keep them from participating in societal functions since homosexuality or the practice thereof is not violating any common law. Marriage is a societal function, it helps society keep order by designating individuals who are pooling their resources to help themselves. Since marriage is a societal function, homosexuals should be able to participate in it fully, unless they are condemned by society or violating a law. If homosexuals are kept from participating in marriage, but are not violating any laws, then they are being discriminated against simply because they are homosexual.
You will note that most state Constitution's that ban homosexuality simply state that the state will not recognize a union between two men or two women, or that a valid union is only between a man and a woman. It is not against the law to practice homosexuality in any state since 2003. Society lets homosexuals participate except for keeping them from marrying / being granted the same privileges granted to heterosexuals after a marriage. Yet the practice of homosexuality is not a crime. Does anyone else see an error here?