Yes, you have that right. Not only would same-sex marriage be illegal, but so would opposite sex marriage for transgender people.

The bill would remove "a court order of sex change" from the list of identifying documents that can be used to obtain marriage licenses in the state. And while other documentation might be found in order to get around the law to obtain said marriage license, the "legislative intent" of the law would be sufficient to allow courts to render any marriages which resulted invalid.

Where would this possibly lead? It could end up with the state of Texas refusing to recognize the existence of the transitioned status of transsexual people for any legal reason. After all, you are nothing more than what was written on your birth certificate.

You see, there was this lawsuit, Littleton v Prange (1999) wherein Christy Lee Littleton attempted to sue her husband's (Christy and Jon Littleton had been married in Kentucky in the 1990s) physician for malpractice connected with his death. The doctor, Mark Prange, contended through his legal team that Littleton had no standing since the marriage was invalid. Chief Justice Phil Hardberger ruled that Christy Lee Littleton was a male because of her chromosomes (those who trolled the past two diaries should especially note this is where your reasoning leads) and so the marriage was not legal…so it didn't matter what the doctor may have done or not done to his patient, because in the eyes of the law Christy Lee was a total stranger.

There is contact information at TransGriot.