1875, from Functions and Disorders of the Reproductive Organs by William Acton:

Women (happily for society) are not very much troubled with sexual feeling of any kind. What men are habitually, women are only exceptionally. It is true, I admit, … there are some few women who have sexual desires so strong that they surpass those of men, and shock public feeling by their consequences. I admit, of course, the existence of sexual excitement terminating even in nymphomania … but, with these sad exceptions, there can be no doubt that sexual feeling in the female is in the majority of cases in abeyance, and that it requires positive and considerable excitement to be roused at all; and even if roused (which in many instances it never can be) it is very moderate compared with that of the male. [as quoted on p.36 of The Social Meaning of Human Sexuality by John Petras, 1978]

1975, from Against Our Will by Susan Brownmiller:

Is it possible that there is some sort of metaphysical justice in the anatomical fact that the male sex organ, which has been misused from time immemorial as a weapon of terror against women, should have at its root an awkward place of painful vulnerability? Acutely conscious of their susceptibility to damage, men have protected their testicles throughout history with armor, supports and forbidding codes of “clean,” above-the-belt fighting. A gentleman’s agreement is understandable — among gentlemen. When women are threatened, as I learned in my self-defense class, “Kick him in the balls, it’s your best maneuver.” How strange it was to hear for the first time in my life that women could fight back, should fight back and make full use of a natural advantage; that it is in our interest to know how to do it. How strange it was to understand with the full force of unexpected revelation that male allusions to psychological defeat, particularly at the hands of a woman, were couched in phrases like emasculation, castration and ball-breaking because of that very special physical vulnerability. [Petras pp.195-6]