This article provides an overview of human reproduction, focusing on the structure and function of the male and female reproductive systems. It discusses the hormones involved in the control of the female menstrual cycle and the differences between spermatogenesis and oogenesis. The timeline of events in embryonic and fetal development is summarized, along with the relationship between the placenta and fetal circulation, lungs, and liver. The importance of the changes to the fetal circulation, lungs, and liver in the readiness for birth is also explained.