Individual instruction in sex matters should be reserved for the diseased mind, for the boy or girl who has already been morbidly instructed. Discussion of immoral sex diseases should be confined to individual talk. This field teachers have already entered. Repeated physical examination of children will detect symptoms of sex abnormality. When detected, the fact and the meaning should be explained to the individual by school physician, school nurse, or school-teacher. While much can be done through mothers' meetings and through individual instruction of parents, the most effective means of improving the general attitude towards sex health is to give the simple truth to the millions of children who have not yet left school. Armed with the A B C's of sex hygiene at school, boys and girls will be prepared to select employment, associates, and newspapers that will permit normal, healthy sex development. Men and women who are leading normal lives, who have plenty of work, sleep, fresh air, nourishing food, amusement, and exercise are unlikely to be sexually abnormal. After all, the question of instruction in sex hygiene will quickly settle itself when it is made a condition of a teacher's certificate that the applicant shall himself or herself know the personal and social reasons for sex health. The woman who does not know how to take care of her own sex health, the man who is ignorant of a woman's special needs, cannot do justice to the requirements of arithmetic, language, and discipline. Whether men and women teachers are mentally, physically, and morally equipped to be sexually normal and to teach the law of sex health will be disclosed as soon as trustees and superintendent dare to ask the necessary questions. Whether an instructor's personality will enable him to fill the minds of children with interests more wholesome, more absorbing than obscene stories or morbid sex curiosity can also be learned. When school-teachers are prepared to teach the social and economic aspects of general health they will quickly solve the problem of instruction in sex health.