For purposes of imposing deductions under the annual earnings test (see § 404.415 ) and the foreign work test (see § 404.417 ), a person who is married to an old-age insurance beneficiary and who is entitled to a mother's or father's insurance benefit or a child's insurance benefit based on the child's disability (and all these benefits are based on the earnings record of some third person) is deemed entitled to such benefit based on the earnings record of the old-age insurance beneficiary to whom he or she is married. This section is effective for months in any taxable year of the old-age insurance beneficiary that begins after August 1958.
20 C.F.R. §404.420