... it may be hoped that the white population of the world will soon cease to increase. The Asiatic races will be longer, and the negroes still longer, before their birth rate falls sufficiently to make their numbers stable without help of war and pestilence. But it is to be hoped that the religious prejudices which have hitherto hampered the spread of birth control will die out, and that ... the whole world will learn not to be unduly prolific. Until that happens, the benefits aimed at by socialism can only be partially realized, and the less prolific races will have to defend themselves against the more prolific by methods which are disgusting even if they are necessary.