Notwithstanding any other provision of this chapter,¹ it shall not be an unlawful employment practice because of sex to differentiate in employment, compensation, terms, conditions or privileges of employment between male and female employees if such differences are otherwise required or permitted by the laws of this state, or by the provisions of Section 703 of the Federal Civil Rights Act of 1964, as amended,² or by the provisions of Section 6(d) of the Federal Fair Labor Standards Act of 1938, as amended;³ nor shall it be an unlawful employment practice because of sex for an employer, pursuant to a plan, to provide differences in annuity, death and survivors' benefits between widows and widowers of employees.