S.D. Codified Laws § 58-33-13.1

An insurance contract may not be denied to an insured or prospective insured on the basis of his or her sex or marital status. The amount of benefits payable, or any term, conditions, or type of coverage shall not be restricted, modified, excluded, or reduced on the basis of the sex or marital status of the insured or prospective insured except to the extent the amount of benefits, term, conditions, or type of coverage vary as a result of the application of rate differentials permitted under this title. However, an insurer may take marital status into account for the purpose of defining persons eligible for dependents benefits. This section shall not affect the right of fraternal benefit societies to determine eligibility requirements for membership. This section shall apply to all contracts delivered or issued for delivery in this state by an insurer on or after July 1, 1980 and to all existing group contracts which are amended on or after July 1, 1980.