Societal conditions for early and high rates of childbearing were replaced by conditions generating late and low levels of fertility common in Western countries. Central among factors shaping the latter behaviour (job insecurity, unstable partnership relationships, expensive housing, and profound changes in norms, values and attitudes) were the following: increasing proportions of young people were acquiring advanced education, a majority of women were gainfully employed, yet women were performing most household maintenance and childrearing duties. Two theories prevailed to explain what caused changes in family formation and fertility trends. One argues that the economic and social crises were the principal causes. The other considered the diffusion of western norms, values and attitudes as the prime factors of change. Neither reveals the root cause: the replacement of state socialist regimes with economic and political institutions of contemporary capitalism. The extraordinarily low period TFRs around 2000 were the result of low fertility of older women born around 1960 overlapping with low fertility of young women born during the 1970s.