California
Family Code – FAM § 7576
(a) After the period for rescission provided in Section 7575 expires, but not later than two years after the effective date provided in subdivision (c) of Section 7573 of a voluntary declaration of parentage, a signatory of the voluntary declaration of parentage may commence a proceeding to challenge the declaration on the basis of fraud, duress, or material mistake of fact.
(b) The limitations period provided in subdivision (a) shall not apply if the voluntary declaration of parentage is void under Section 7573.5 .
(c) This section shall become operative on January 1, 2020.