(5) Some phases of the "woman's movement" have without doubt tended to lessen the birth rate in certain sections of American society. Some of the leaders of the woman's movement have advocated, for example, that women should choose a single life, while others have advocated that families should not have more than two children. Mrs. Ida Husted Harper, indeed, has gone so far as to claim that if families would have but two children this would be a cure-all for many social troubles. Indeed, this ideal of two children in the family has been so widely disseminated in this country that it is often spoken of as the "American Idea." Of course, such teachings could not be without some effect. Without attempting to reply to the advocates of this theory of but two children to a family, it will be sufficient to remark that for a population simply to remain stationary three children at least must be born to each family on the average; otherwise, if only two children are born, as one of the children is apt to die or fail to marry, the population will actually decrease in numbers. Under the best modern conditions one out of three children now born either fails to live to maturity or fails to reproduce. There must be, therefore, more than three children born to the average family for a population to grow. From the sociological point of view the ideal family would seem to be one in which from three to six children are born. (6) Finally, not all of the childless and small families in the native American stock are due by any means to voluntary causes, or even involuntary causes of the kind that we have mentioned. There are also certain other obscure physiological causes at work producing sterility in American women. The sterility of American women is greater than that of any other civilized population, even apart from the causes which have just been mentioned. Some say this is due to physical deterioration in the native white American stock, and there are other things which seem to point in that direction. It may be, however, that this deterioration is in no sense racial, but only individual, affecting certain individuals who lead a relatively unnatural life. Our American civilization puts a great strain upon certain elements of our population, and this strain in many cases falls even more upon the women than upon the men. The social life of the American people, in other words, is oftentimes such as to produce exhaustion and physical degeneracy, and this shows itself in the women of a population first of all in sterility. It is evident that the remedy for this cause is a more natural and more simple life on the part of all, if it is possible to bring this about.