Christianity, with its extension of the idea of personality and corresponding lack of consideration for the race, in opposition to the world of antiquity, made marriage the affair of the individual. The development of love has carried on the liberation that Christianity began. As stated in the first chapter, the champions of Christianity constantly admit the right both to remain unmarried and to limit the birth of children, if both are only the result of abstinence. To the evolutionist, on the other hand, only the cause, not the manner, is the deciding point. Danger to the possible children or to the mother herself; the fear of pecuniary or personal insufficiency for the bringing-up of the children; the desire of using all one’s powers and resources for an important life-work; a Malthusian point of view in the question of population—these and other motives are regarded by the evolutionist as good reasons for limiting or altogether abstaining from parentage. And in this respect the individual is allowed freedom of choice also as regards the method which best agrees with the opinion of science on hygiene, and with his own on morality and fitness. As soon as it is recognised that the individual is also an end in himself, with the right and duty of satisfying in the first place his own demands according to his nature, then it must remain the private affair of the individual whether he will either leave altogether unfulfilled his mission as a member of the race, or whether he will limit its fulfilment. But as the individual cannot attain his highest life-enhancement or fulfil his own purpose otherwise than in connection with the race, he acquires duties also towards it, and not least as a sexual being. If life has given the individual a lot which renders moral parentage possible, and conditions which are favourable to new lives, then the only moral limitation of the number of children is one which—in and by means of the individual’s own life-enhancement and that of the children—is to the advantage of the whole community. But when only petty and selfish reasons—such as considerations of the children’s inheritance, personal good-living and voluptuousness, beauty and comfort—determine fathers and mothers to keep the number of their children below the average required to secure the due increase of population, then their conduct is anti-social. A person, on the other hand, who is content with few or no children, because he or she has a work to perform, may be able to compensate society by the production of another class of value.