This article explores the changing institutional and technological frameworks of childbirth practices in Japan, highlighting the historical dynamism and the normative dimensions of women's experiences. This article shows how childbirth in Japan was subject to a very powerful and far-reaching process of medicalization going back to the mid-nineteenth century. In present-day Japan, the drive towards high-tech medicalization remains strong, but there is also an emphasis on the need to be "natural" and "healthy" and to avoid unnecessary medical interventions in the body. These two seemingly contradictory sets of demands are an important feature of contemporary Japanese society. Their coexistence is only possible due to the continuing hold of a system of moral responsibility that emphasizes the duty of mothers to do whatever is necessary in terms of medical care to protect the safety and the well-being of their babies.