"Some commentators have drawn attention to the divergent courses of the fertility rates in the two parts of Bengal. In Indian West Bengal, which is three quarters Hindu, the fertility rate is 2.07, below the re- placement level. The contrast with Muslim Bangladesh, where the transition has been blocked, is striking. A shared language should have led to a convergence through cultural contagion, but a pietistic Islam seems to have frozen changes in patterns of thought in Bangladesh and, as a repercussion, provoked a halt to the transition. But a consideration of educational patterns leads to a rejection of the hypothesis of a direct effect of the religious variable on fertility."