I know this topic is pretty old, but I thought others that were researching the process of changing the gender marker in Texas might find this information helpful. I found two websites that outline the process fairly well. I would post links, but I got called out for that a some time ago, so I just avoid doing it. Google these and I'm sure you'll find 'em.
Texas Name and Gender Marker Change
Travis County Law Library (which has a section on gender/name under "Other")
The two sites outline the process and provide sample forms and letters. Highlights: submit change petition, letters from physician(s) and possibly therapist, fingerprint card and a background check if you've been convicted of certain crimes. According to the site, there is no court fee for a gender marker change. Name changes are typically just less than $300. You do not have to have SRS.
Okay, so here's my dumb question of the day perhaps better asked of a lawyer. What if you petition the court and get the order for gender change and don't proceed with contacting all the other agencies, companies, etc? Other than the court record, has anything really changed?
Hope this helps,
--AshleyP