Ward also pointed out that for each of these forms of love there is a correlative hate. This force of repulsion is often greater than the correlative love. Jealousy often leads to violent and destructive actions. Race hatred frequently becomes a vicious, brutal, and widespread sentiment that paralyzes all tendencies toward world progress. Marriage institutions have developed from the operation of the reproductive forces. Polygamy, polyandry, and a score of other types of marriage have arisen, although monogamy has demonstrated itself to be the superior type of marriage institution. The reproductive forces have led to numerous sexuo-social inequalities. Men and women have come to occupy separate spheres of activity, and to represent distinct social conditions.[XVII-30] Although the two sexes live together and appear to be companions, they are in fact dwelling in separate worlds and on different planes. There are several principal inequalities. (1) There is an inequality of dress, which has loaded woman with ornaments and caused her an enormous amount of disease and suffering. (2) There is an inequality of duties, which has kept woman confined to the house, and made a slave or a pampered pet of her. (3) There is an inequality of education. Society has shut woman in the past from all opportunities for gaining knowledge by experience. Moreover, society has seen fit to debar women from the knowledge that is acquired by instruction. (4) An inequality of rights has meant that women have been discriminated against before the law. Without direct representation in legislatures, women have suffered in proprietary matters. (5) A general sex inequality has at times made woman the property or the slave of man. In short, women have been denied, until with recent years, entrance to the higher intellectual forms of activity and at the same time denied social and political rights. Reverting to Ward’s classification of desires, we may now proceed to a discussion of the third set of forces, the sociogenetic. In contradistinction to the nutritive and the reproductive desires, or to the ontogenetic and the phylogenetic forces, respectively, the sociogenetic forces lead directly to race, or social, improvement. The ontogenetic forces guarantee individual preservation; the phylogenetic, race preservation; and the sociogenetic, race and social progress. Ward classified the sociogenetic forces as moral, esthetic, and intellectual.[XVII-31]