https://s044a90.ssa.gov/apps10/poms.nsf/lnx/0100202142RM 00202.142 Form SS-5 Item 8.B. - Mother's SSN
B. POLICY - VALID REASON FOR NOT PROVIDING MOTHER'S SSN
Valid reasons for not providing the mother's SSN are as follows:
-- The mother does not have an SSN.
If the applicant has a valid reason for not providing the mother's SSN write the words “NO SSN” or “UNKNOWN”
https://s044a90.ssa.gov/apps10/poms.nsf/lnx/0100202147RM 00202.147 Form SS-5 Item 9.B. — Father's SSN
B. POLICY - VALID REASON FOR NOT PROVIDING FATHER'S SSN
Valid reasons for not providing the father's SSN are as follows:
-- The father does not have an SSN.
If the applicant has a valid reason for not providing the father's SSN write the words “NO SSN” or “UNKNOWN”, as appropriate, in item 9B.