_Children from four to seven years._—At the period of four to seven years of age, the child’s curiosity about the origin of man is awakened. When he approaches his parents with the question, “Whence do babies come from?” he must not be put off with stork-stories and false ideas, or met with evasive answers. The mother should explain to the child that the baby grows from a seed implanted in the mother’s body, just as the flower grows from a seed sown in the mother Earth. After the child has been told of his origin he should be admonished not to talk of these intimate subjects with others. He should be warned against allowing any one, little friends or adults, nurse or teacher, to touch or play with any part of his body. If an attempt be made by any one, no matter who it is, be it a little friend, brother, sister, etc., to touch his body, the child must be taught to report the fact immediately to his parents. _Children from seven to ten years._—At the period of seven to ten years of age, the child ought to receive its first real sex-lesson by teaching him the anatomy of the sexual organs of the plant. The child is told about the cell being the basis of all organic life. The different modes of reproduction is explained to him. Then we go over to the study of phanerogamous plants and show him that the flower, the most beautiful part of the plant, is nothing else but the genitals of the plant. We then analyze every part of the flower, the male and the female principles. In this way the child will become accustomed to hear, without apprehension or any thought of impropriety, terms like male and female germ-cells, ovum, ovary, etc., terms which are now considered to be unspeakable, save behind closed doors and then only with low breath. _Children from ten to thirteen years._—At the next period from ten to thirteen years of age, we may begin to explain the sex-phenomena in the animal kingdom. It is best to follow the pedigree of the living beings from the lowest, the unicellular animals, to the highest, the mammals. The teacher could even describe to the children the complicated indirect cell division, called “Mitosis,” in order to impress upon their minds the great importance which the creative power of the universe attributes to the correct halving of the nuclear substance of the cell. The child should then get better acquainted with the different modes of reproduction, the binary fission, the budding, the sporulation, the conjugation and the different kinds of the latter. The child may now learn to know the difference between the hermaphroditic animals and sex-animals, between sperm-cells and egg-cells. It may learn what is meant by metamorphosis, by external and internal fertilization, by ovulation and impregnation.