Mass. Gen. Laws ch. 209C, § 25
(i) the plaintiff is or was the defendant to:
(i) Subject to subsection (j), the court shall adjudicate a plaintiff with standing in a proceeding commenced under this section to be a legal parent of the subject child if the plaintiff demonstrates by clear and convincing evidence that:
(vi) each parent of the child consented to the bonded and dependent relationship required under clause (v); provided, however, that for the purposes of this section, consent shall include that each parent, over a period of not less than 6 months: