Can a sixteen year old girl who is pregnant move in with her nineteen year old boyfriend without parental consent in Texas?

NO. Being pregnant does not give you any 'adult rights'. You would be a 'runaway' and boyfriend can face criminal charges for taking you in. Plus, while your parents are chatting with the police they just might mention the fact that an adult impregnated their minor child who is *under the age of sexual consent*. That's big time illegal.