I do believe that the myth of Ginger’s Sexuality is based on history and how red heads were used to sell products and sex in the 40’s, 50’s and 60’s.
Most pin up girls before photography was wide spread, often show animations of sexy red heads in advertisements. Here is one theory from Steve Sailer, that I have to agree with.
Steve Sailer said: “One theory I have is that in the middle of the 20th Century, the existing hair dyes worked better for brunette-to-redhead transformations than for brunette-to-blonde…So, perhaps attention-seeking women in the mid-20th Century were more likely to wind up redheads than blondes, which in turn generated a lot of buzz about what that special something was that redheads had that made them so fascinating.”
And by the mid-20th century, Technicolor in Hollywood films was in more widespread use so redheads showed to advantage. In the black and white “Thin Man” films of the 30’s and 40’s, you can’t tell that Myrna Loy was a redhead, just as you couldn’t tell Rita Hayworth had dyed her black hair red–it looked brown onscreen. But in the Technicolor films of the 50’s, the red hair of actresses like Arlene Dahl and Rhonda Fleming was part of their appeal. Audiences could see that Deborah Kerr and Kate Hepburn had lots of red in their hair, too.
Also the rise of the red-headed Suzy Parker, fashion’s first “super model”, in the 40’s and 50’s was probably a factor.