The effects of parents' education on marital fertility are analysed with data from 38 Surveys in the WFS programme, and a two-parameter model in which the age-dependent level of fertility and a duration-dependent slope of fertility are estimated. The level parameter reflects post-partum infecundity and, in some populations, contraceptive spacing of births. The slope parameter reflects parity-specific birth control. The effects of the husband's and of the wife's education are estimated, both before and after adjustment for other socio-economic factors. The schooling of the wife emerges as a more decisive influence on fertility than that of the husband, with substantial net effects even after controlling for urban-rural residence, husband's socio-economic status and wife's employment. In Latin America and the Arab states, monotonic declines in marital fertility are found, as the level of the wife's education increases. However, in many Asian and African populations, the highest fertility is observed among women with moderate exposure to schooling, because the relaxation of traditional spacing mechanisms is not matched by increased birth control. This regional diversity cannot be explained convincingly by national levels of economic development or efforts made to popularize contraception, but appears to relect ill-understood cultural factors.