This book provides a key to understanding why there was an increase in extra-marital fertility in Japan from the 1990s to the 2010s, particularly between 1995 and 2015, and the factors which contribute to the multistratification of unmarried mothers, the number of which has increased ensuingly. It also allows for international comparison by providing data on outcomes of extra-marital childbirth.

Previously, it was believed that the idea of a ''second demographic transition'' did not apply to Japan, which had a relatively low rate of extra-marital fertility. However, more recently, though still at a low level, a subtle but gradual rise is seen in the number of women who become unmarried mothers as a result of births outside marriage.

This trend suggests that the social environment surrounding pregnancy, childbirth, and marriage is changing. In this book, various data such as national statistics, nationwide surveys, and media discourse are analysed with a view to revealing the factors affecting unmarried women''s decisions when they discover they are pregnant. Various matters are discussed, such as changes in sexual activity and contraceptive use, advance in reproductive technology, the law and government policies pertaining to adoption, social consciousness towards unwed mothers, the change in perception of abortion from the religious perspective, and difference of socioeconomic status depending on the women''s occupation.

If we assume that, unlike the first demographic transition model, the ''second demographic transition'' may show a similar direction but be on a different scale according to the country, it is possible to say that Japan too is experiencing the ''second demographic transition''.