The inclusion of the following factors in our concept "sexual" amply suffices for all practical purposes in ordinary life: the contrast between the sexes, the attainment of sexual excitement, the function of reproduction, the characteristic of an indecency that must be kept concealed. But this is no longer satisfactory to science. For through careful examinations, rendered possible only by the sacrifices and the unselfishness of the subjects, we have come in contact with groups of human beings whose sexual life deviates strikingly from the average. One group among them, the "perverse," have, as it were, crossed off the difference between the sexes from their program. Only the same sex can arouse their sexual desires; the other sex, even the sexual parts, no longer serve as objects for their sexual desires, and in extreme cases, become a subject for disgust. They have to that extent, of course, foregone any participation in reproduction. We call such persons homosexual or inverted. Often, though not always, they are men and women of high physical, intellectual and ethical development, who are affected only with this one portentous abnormality. Through their scientific leaders they proclaim themselves to be a special species of mankind, "a third sex," which shares equal rights with the two other sexes. Perhaps we shall have occasion to examine their claims critically. Of course they are not, as they would like to claim, the "elect" of humanity, but comprise just as many worthless second-rate individuals as those who possess a different sexual organization.