By Alan B. Combs
This tale was told to us in an organic chemistry class while I was an undergraduate in the 60s, so I cannot claim original credit for it. The lecture was about amino-acids and their structures. In passing, the prof told us that red-heads have a lot more of the amino-acid cysteine in their hair than do folks with other hair colors. Thus, he said that his fellow male graduate students called a rather virginal, aloof, red-haired female graduate student the Cysteine Madonna.