The capacity for sexual intercourse is influenced to a varying degree by age. Sexual capacity is regarded as coincident with puberty. In judging the sexual capacity of a youth, age is of less moment than the degree of physical development. I have seen a male child of five years of age with as complete development of the sexual organs as an adult, and with a deep voice. At the other extreme of life it is impossible to lay down any definite limit to sexual capacity. Although it is regarded as diminishing with age, yet there are many instances of procreative power in men of an advanced age. The principal points for consideration in reference to impotence and sterility in the male are: (_a_) Does the condition prevent the secretion of semen? (_b_) Does it prevent the conveyance of semen to the vagina? =Impotence and Sterility in the Female.=--As in the male, these may be associated with organic defect or functional disorder. The external organs may be absent, with or without the internal. The vagina may be wanting through lack of development, or it may be obstructed by mal-development or the result of disease. Again, the external organs may be present, but the internal absent in whole or part. The hymen may be imperforate, or unusually tough. Diseases of the uterus often give rise to sterility. Vaginismus, in which attempts at coïtus cause painful spasm, may prevent intercourse. In reference to functional disorders are to be noted extreme debility, constant leucorrhœa, dysmenorrhœa, menorrhagia, and amenorrhœa, all of which may be associated with or causative factors in sterility. Emotional psychical conditions may prevent sexual intercourse in women. General diseases, however, do not necessarily prevent intercourse, as the woman may remain a passive agent, neither is bodily deformity always a barrier to the act. The advent of sexual capacity in women is regarded as coincident with the onset of the menses, about fourteen years of age, but pregnancy has been known to take place prior to the first menstrual period. The age at which the menses first appear varies in no small degree. It has been known to occur during the first year of life, and pregnancy has been known to occur as early as the eighth year. The menopause in women is regarded as coincident with loss of procreative power. Women as a rule cease to menstruate at forty-five years of age, but in not a few the function persists until fifty, in exceptional cases to a more advanced age. It is rare for a woman to bear children after the menopause, but exceptions have been known to take place.