In modern times, the legality of sunbathing bare-breasted might seem like a question for women only. But back in the 1930s, it was American men campaigning to “free the nipple” after the shirtless success of Johnny Weissmuller in 1932’s Tarzan the Ape Man, and Clark Gable in 1934’s It Happened One Night awakened them to the liberating possibility of wearing something other than a full swimming costume to the beach. Only after a number of protests (42 men who swam together sans shirt in Atlantic City were arrested and fined in 1935) was “bareback bathing”  finally legalized in 1937.

For women, the debate is not yet settled. Topless sunbathing’s glamorous reputation was born during the sexual revolution of the 1960s. In 1964, fashion designer Rudi Gernreich created a topl...