The greatest possible good of sex-education will not be secured if it stops with early adolescent years. There are many problems of sex in relation to society, particularly in relation to monogamic marriage, that young people should be led to consider in the late teens and early twenties. Our sex-education system will not be completely organized until we find ways and means for carrying the instruction by lectures, conferences, and books beyond the years commonly occupied by public-school education. Colleges and other higher educational institutions may contribute somewhat to this advanced sex-instruction; but obviously the great majority of maturing young people cannot be reached personally except by instruction arranged in churches, the Y.M.C.A., and the Y.W.C.A., evening schools, and other such institutions. In many respects this proposed instruction for maturing young people is of very great importance and deserves encouragement such as has not yet been given by those who have written and lectured in favor of a movement for sex-education of young people. [Sidenote: The larger sex-education.] In conclusion of this introductory lecture, let me say that I have tried to suggest in a general survey that sex-education in its largest outlook touches great problems of life in very many ways. I have also tried to convince that it is far more than merely a school subject, limited entirely to a curriculum extended over a few years. This is the common misunderstanding arising from the familiar use of the word "education." As opposed to this narrow conception, I understand sex-education, the larger sex-education, to be a collective term designating all organized effort, both in and out of schools, toward instructing and influencing young people with regard to the problems of sex. Here we have returned to the central thought of the definition with which this lecture opened, and which I emphasize because it is the foundation of all future lectures: The larger sex-education includes all scientific, ethical, social, and religious instruction and influence which in any way may help young people prepare to meet the problems of life in relation to sex. II THE PROBLEMS FOR SEX-EDUCATION Sec. 5. _Sex Problems and the Need of Special Knowledge_ [Sidenote: Arguments for sex-education.] In these lectures I shall discuss the great sex problems towards the solution of which knowledge conveyed by special education may help. These problems offer reasons or arguments in favor of sex-education, and I shall attempt to present them from this point of view. I shall at the same time point out in preliminary outline how organized instruction may apply more or less directly to the sex problems that seem to show the need of educational attack, but in later lectures the organization of instruction will be considered more specifically. [Sidenote: Propagandism needed.]