The 1940-1950 changes in number of children ever born among ever-married women under 35 years of age as compared with those 35 years of age and over. Among the younger women this fertility rate increased and the increase was sharpest at ages 25-29. Among the older women the rate was lower than in 1940. The increase in the younger group was sharpest in the "upper" educational and occupational groups. Since these classes were those of the lowest fertility in 1940, the 1940-1950 increases tended to diminish the range of fertility differentials by education and occupation. Nevertheless, the inverse relation of lifetime fertility to socio-economic status persisted albeit in somewhat diminished strength in 1950. The 1940-1950 changes in fertility ratios by education and occupation are more drastic than changes in total fertility rates because the former reflect more exclusively the differential increase in current fertility. In some age groups, particularly 30-34, the highest fertility ratio is for college graduates.