It is indeed possible that this “third sex,” that hermaphrodites, homosexual individuals, sexual “intermediate stages,” also play a certain part in the great process of civilization. But their significance is slight and limited, if for this reason alone because from these individuals the possibility of transmission by inheritance of valuable peculiarities is cut off, and hence the possibility of a future perfectibility, of true “progress,” is excluded. There are =two= sexes only on which every true advance in civilization depends--the genuine man and the genuine woman. All other varieties are ultimately no more than phantoms, monstrosities, vestiges of primitive sexual conditions. Very ably has Mantegazza described the intimate relationship between these dreams of the “third sex” and the fantastic aberration of the sexual impulse. He writes: “While the pathology of love recognizes in many sexual aberrations the obscure traces of a general hermaphroditism, imagination, which works faster than science, shows us the possibility that in more complicated creations sexual differentiation might be more than twofold, so that in such worlds sexual reproduction might be effected by a more elaborate division of labour. Thus, in the cynical or sceptical distinction between platonic, sexual, and licentious love, we see the first traces of new and monstrous possibilities of sexual union, on the one hand reflecting the sublimity of the supersensual, and on the other more brutal than the most horrible sexual aberration.” In reality, it is only for normal heterosexual love between a normal man and a normal woman that it is possible to find an unimpeachable sanction. Only this love, continually more differentiated and more individualized, will play a part in the future course of civilization.