> Child-based tax deductions should be based on what children a couple have, not on what gender the couple are.
Should... and are. You can receive child-based tax deductions even if you are not married at all. Whenever I hear the "deductions are for the children" thing brought up I take it as a clear sign that the person saying it has very limited life experience.
And why do you oppose gay adoption? That's nothing to do with changing the definition of marriage, or tax issues...