20 CFR 404.715: When evidence of age is needed.

(a) If you apply for benefits, we will ask for evidence of age which shows your date of birth unless you are applying for—

(1) A lump-sum death payment;

(2) A wife's benefit and you have the insured person's child in your care;

(3) A mother's or father's benefit; or

(4) A disability benefit (or for a period of disability) and neither your eligibility nor benefit amount depends upon your age.

(b) If you apply for wife's benefits while under age 62 or if you apply for a mother's or father's benefit, you will be asked for evidence of the date of birth of the insured person's children in your care.

(c) If you apply for benefits on the earnings record of a deceased person, you may be asked for evidence of his or her age if this is needed to decide whether he or she was insured at the time of death or what benefit amount is payable to you.