Gender is a legitimate basis for organizing our society and its affairs that would never be countenanced with any other criteria. Men and women are different and that's reflected in our laws and its not discrimination to acknowledge gender is relevant to the definition of marriage.
"Show me just what Mohammed brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached." - Manuel II Palelologus
What you consider legitimate and a basis for denying these taxpaying adults from getting married are overriden buy human rights. Your definition and opinions are just that, yours. The opinions of the majority are just that. The majorty cannot vote against the rights of others. Otherwise, blacks would still be in segragated schools.
That's why everyone here whined so much when the conservative Cal Supreme court rendered the decision that did. They can't understand this basic concept of freedom because thay can't let those filthy homos have anything.