Yes, there is.
In 1924, the Simpson Act closed the floodgates of immigration, and they remained closed until 1965 when Hubert Humphrey and Ted Kennedy reopened them. There were a number of bills packaged with the Simpson Act, and one of them laid an unfunded mandate on the states to maintain birth, death and marriage certificates.
Here is where it gets strange. The entity that pushed heavily for this law was not exactly a federal agency. It was the Federal Reserve. As to why the Fed thought this was important is something I can't consider without donning my tinfoil hat.
Sucks having to make the distinction, but ‘heterosexual marriage’ is the foundation for a strong family that would raise responsible children, and likewise future taxpayers.