Does this law actually exist? Can you please point me to the text of it?

I have been under the impression that, in the state of Texas, a person who is under 21 can drink alcohol legally if their parents are serving them, or if they’re married, their spouse. Is it true? If so, can you please help me find the law so I can read it for myself? I don’t even know where to begin if I was going to google it. Thanks!

EDIT: And could you please give me a link as well?