20 C.F.R. § 404.339 : Employees' Benefits — SOCIAL SECURITY ADMINISTRATION — FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) — OLD-AGE, DISABILITY, DEPENDENTS' AND SURVIVORS' INSURANCE BENEFITS; PERIOD OF DISABILITY —BENEFITS FOR SPOUSES AND DIVORCED SPOUSES — How do I become entitled to mother's or father's benefits as a surviving spouse?

You may be entitled as the widow or widower to mother's or father's benefits on the earnings record of someone who was fully or currently insured when he or she died. You are entitled to these benefits if-

(a) You are the widow or widower of the insured and meet the conditions described in §404.335(a);
(b) You apply for these benefits; or you were entitled to wife's benefits for the month before the insured died;
(c) You are unmarried;
(d) You are not entitled to widow's or widower's benefits, or to an old-age benefit that is equal to or larger than the full mother's or father's benefit; and
(e) You have in your care the insured's child who is entitled to child's benefits and he or she is under 16 years old or is disabled. Sections 404.348 and 404.349 describe when a child is in your care.

20 C.F.R. §404.339

44 FR 34481, 6/15/1979, as amended at 48 FR 21927, 5/16/1983; 73 FR 40967, 7/17/2008