Fam. Code, § 7551

(a) Except as provided in subdivisions (b) and (c), in a civil action or proceeding in which parentage is a relevant fact, the court may, upon its own initiative or upon suggestion made by or on behalf of any person who is involved, and shall upon motion of any party to the action or proceeding made at a time so as not to delay the proceedings unduly, order the woman who gave birth, the child, and the alleged genetic parent to submit to genetic testing.

(b) (1) Genetic testing shall not be used for any of the following purposes:

(A) To challenge the parentage of a person who is a parent pursuant to subdivision (a) of Section 7613, except to resolve a dispute whether the child was conceived through assisted reproduction.

(B) To challenge the parentage of a person who is a parent pursuant to Section 7962, except to resolve a dispute whether the gestational carrier surrogate is a genetic parent.

(C) To establish the parentage of a person who is a donor pursuant to Section 7613, except to resolve a dispute whether the child was conceived through assisted reproduction.

(2) If the child has a presumed parent pursuant to Section 7540, a motion for genetic testing is governed by Section 7541.

(3) If the child has a parent whose parentage has been previously established in a judgment, a request for genetic testing shall be governed by Section 7647.7.

(4) A court shall not order genetic testing if the genetic testing would be used to establish the parentage of a person who is prohibited under this division from establishing parentage based on evidence of genetic testing.

(c) A court shall not order in utero genetic testing.

(d) In any case under this division in which genetic testing is ordered, the following shall apply:

(1) If a party refuses to submit to genetic testing, the court may resolve the question of parentage against that party or enforce its order if the rights of others and the interests of justice so require.

(2) The refusal of a party to submit to genetic testing is admissible in evidence in any proceeding to determine parentage.

(3) If two or more persons are subject to court-ordered genetic testing, the court may order that the testing be completed concurrently or sequentially.

(4) Genetic testing of a woman who gave birth to a child is not a condition precedent to the testing of the child and a person whose genetic parentage of the child is being determined. If the woman is unavailable for genetic testing, the court may order genetic testing of the child and each person whose genetic parentage of the child is at issue.

(5) An order under this division for genetic testing is enforceable by contempt.