Yes there is, the 14th Amendment.Historical backlash leads to harm for homosexuals and heterosexual alike. Same sex marriage is like our daughters, sisters, mother and wives in front line combat. There is no gender equality right in the Constitution.
"All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside. No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws."
I'm going to get a good laugh at you every time you start foaming at the mouth at women in combat. You hate gays, you hate women. Who do you like?