...and at least one of them isn’t the girl’s parent.
What tipped you off? ;-)
Biologically no, but legally perhaps. While only a handful of states recognize gay marriage, many states - and I think TX (but am not sure) - recognizes gay adoption. Plus, the US is signatory to certain international treaties that recognize adoption proceedings in foreign countries. IOW, if this other lesbian actually adopted her "partner's" child, then they are both parents, in the eyes of US federal and most state law.