Tex. Family Code § 160.503

(a) Genetic testing must be of a type reasonably relied on by experts in the field of genetic testing. The testing must be performed in a testing laboratory accredited by:

(1) the American Association of Blood Banks, or a successor to its functions;

(2) the American Society for Histocompatibility and Immunogenetics, or a successor to its functions; or

(3) an accrediting body designated by the federal secretary of health and human services.

(b) A specimen used in genetic testing may consist of one or more samples, or a combination of samples, of blood, buccal cells, bone, hair, or other body tissue or fluid. The specimen used in the testing is not required to be of the same kind for each individual undergoing genetic testing.

(c) Based on the ethnic or racial group of an individual, the testing laboratory shall determine the databases from which to select frequencies for use in the calculation of the probability of paternity of the individual. If there is disagreement as to the testing laboratory's choice:

(1) the objecting individual may require the testing laboratory, not later than the 30th day after the date of receipt of the report of the test, to recalculate the probability of paternity using an ethnic or racial group different from that used by the laboratory;

(2) the individual objecting to the testing laboratory's initial choice shall:

(A) if the frequencies are not available to the testing laboratory for the ethnic or racial group requested, provide the requested frequencies compiled in a manner recognized by accrediting bodies; or

(B) engage another testing laboratory to perform the calculations; and

(3) the testing laboratory may use its own statistical estimate if there is a question regarding which ethnic or racial group is appropriate and, if available, shall calculate the frequencies using statistics for any other ethnic or racial group requested.

(d) If, after recalculation using a different ethnic or racial group, genetic testing does not rebuttably identify a man as the father of a child under Section 160.505, an individual who has been tested may be required to submit to additional genetic testing.