There will be a death if there is a birth. Similarly, there probably will be a birth if there is a death. If we know only the death of human beings without comparative knowledge about birth, the understanding of life and death of human beings will be incomplete. The Yogācarābhūmi Sūtra of Buddhism is a written documentation that has unimaginable detailed description about the fertilization of ova and the further development of embryo in the uterus of the mother. By comparing the descriptions in the Yogācarābhūmi Sūtra of Buddhism and the texts of modern embryology, we found that though a little macroscopic, the descriptions in the Yogācarābhūmi Sūtra of Buddhism are rather detailed and correct as judged by the standard of medical science at that time. The Yogācarābhūmi Sūtra of Buddhism can be viewed as the beginning of modern human embryology; it can even be viewed as the first classic book on human embryology in history. It was really incredible that Shakyamuni could make such detailed eye-witness observation and description on the development of human embryo without using any instrument. Since Shakyamuni lived earlier than Aristotle and since he had made more correct and detailed descriptions about the formation and development of human embryo than Aristotle, Shakyamuni should be the first or father of human embryology, and the Yogācarābhūmi Sūtra of Buddhism should be the first book on human embryology in history.
