Aristotle's comprehensive account of animal reproduction. Across five books, he examines how every kind of animal generates offspring — from the mating habits of fish to the development of the human embryo — always asking why nature does things the way it does.
Start ReadingMale and female generative organs and the nature of semen. Aristotle describes the reproductive anatomy of various animals and argues that semen contributes form to the embryo while the female contributes matter.
The mechanism of generation. Aristotle explains how conception occurs, how the embryo develops, and why some animals are viviparous, some oviparous, and some produce larvae.
Birth, embryonic development, and sex determination. Aristotle examines the stages of foetal growth, explains what determines whether offspring are male or female, and discusses multiple births and monstrous formations.
Variations in offspring. Aristotle examines why offspring resemble their parents (or don't), the inheritance of characteristics, and the factors that produce variations in colour, hair, and bodily proportions.
Secondary characteristics and generation in lower animals. Aristotle examines features like hair colour, eye colour, voice, teeth, and ageing, then discusses reproduction in birds, fish, insects, and testaceans.