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In this paper, we study the evolution of the distribution of fertility rates across the world from 1950 to 2005 using parametric mixture models. We demonstrate the existence of twin peaks and the division of the world’s countries in two distinct components: a high-fertility regime and a low-fertility regime. Whereas the significance of twin peaks vanishes over time, the two fertility regimes continue to exists over the whole observation period. In 1950, about two thirds of the world’s countries belonged to the high-fertility regime and the rest constituted the low-fertility regime. By the year 2005, this picture has reversed. Within both the low- and the high-fertility regime, the average fertility rate declined, with a larger absolute decline within the high-fertility regime. Visually, the two peaks moved closer together. For the low-fertility regime, we find both β- and σ -convergence but we cannot establish any convergence pattern for the high-fertility regime. Our results support the idea of conditional convergence where the condition is the successful initiation of the fertility transition. The results are less supportive of the existence of a unique high-fertility equilibrium. Copyright Springer-Verlag Berlin Heidelberg 2015