Since "Equal Protection" For Women 
Justice Douglas wrote:  "I suppose that, in 1920, when the Nineteenth Amendment was ratified giving women the right to vote, it was assumed by most constitutional experts that there was no relief by way of the Equal Protection Clause of the Fourteenth Amendment. In Minor v. Happersett, 21Wall. 162, the Court held in the 1874 Term that a State could constitutionally restrict the franchise to men. While the Fourteenth Amendment was relied upon, the thrust of the opinion was directed at the Privileges and Immunities Clause with a subsidiary reference to the Due Process Clause. It was much later, indeed not until the 1961 Term -- nearly a century after the Fourteenth Amendment was adopted -- that discrimination against voters on grounds other than race was struck down."