Does it matter? This is pure science:
Of all members of the mammalian family, civilized man alone is a victim of an exaggerated and morbid sexual urge, a condition which he has inflicted, to a certain extent, on the animals which he has domesticated and which have adopted his diet, especially the dog. Wild animals in a state of nature practice copulation only at certain mating seasons for the purpose of reproduction. Civilized man practices this act at all times, and in most cases without intention to conceive. On the other hand, so-called savages and primitive races leading more natural lives and who follow their natural instincts to a greater extent are far chaste in their sexual behavior, as noted by Havelock Ellis. Such considerations must lead one to the conclusion that the sex life of civilized men is unnatural and that the excessive manifestation of the sex urge among them is due to certain aphrodisiacal stimuli rather than to natural instinct; among such stimuli are a high-protein meat diet (accompanied by physical inactivity), the use of tobacco, alcohol and coffee, sexually stimulating literature, dramas, motion pictures, conversation, etc. For these reasons civilized man has departed from the natural law, obeyed by animal and primitive races, which requires the separation of the sexes during pregnancy and lactation, for the benefit of both mother and child. Violation of this law may account for the large number of physically and mentally defective offspring produced by civilized races as compared with animals and primitive peoples.