The happiness of all human beings, men and women, depends largely on their rational solution of the sexual problem. Sex and the part it plays in human life cannot be ignored. In the case of animals sex plays a simpler and less complex role. It is a purely natural and instinctive function whose underlying purpose is the perpetuation of the species. It is not complicated by the many incidental phenomena which result, in mans case, from psychologic, economic, moral and religious causes. Climate, social conditions, individual modes of life and work, alcohol, wealth and poverty, and other factors affect sexual activity in human beings.
Sexual love, which is practically unknown to the animals, is a special development of the sex urge in the human soul. The deeper purpose of the sex function in human beings, likewise, is procreation, the reproduction of species.