Unless the 25 year old man is an employee at a "public or private primary or secondary school" then he can legally have sexual relations with a 17 year old in the State of Texas. The parents of the 17 year old would have to seek other remedies against the 25 year old besides a criminal prosecution.
I agree with Mr. Cook. The only situation in which a person can be criminally liable in your hypothetical would be in the educator/student context. For instance, if a 25 year old teacher has sex with his/her 17 year old student - that is a felony. Otherwise, there is no proihibition under the Texas Penal Code for such a relationship.