PIP: The view is tested that the total fertility rate (TFR) is less than the total lifetime postnuptial fertility rate (TDFR) when age at marriage grows, and that the TFR is more than the TDFR when age at marriage declines. During 1970-79 in China the marriage age increased from 20.3 to 23.1 years. During this period the average TFR was 4.006, under the average TDFR of 4.602. Deferred marriage is determined to contribute to a 12.95% decline in fertility or a reduction by 28.2176 million births. During 1979-84 marriage age decreased from 23.0 to 21.7 years. After 1982 the TFR was higher than the TDFR. The decline in marriage age accounted for 3% of the 85,879,600 million births during 1982-85 or 2,576,388 births. Marriage age increased again slightly after 1986, and the TFR was lower than the TDFR. During 1986-92 marriage age increased slowly from 21.8 to 22.6 years, and the TFR remained lower (2.17 compared to a TDFR of 2.31). The decline in the marital fertility rate was by 6%. After 1949 the highest deferred marriage rate was in 1979 (52.9%) and 1980 (52.8%). The proportion deferring marriage declined until 1985 to 38.2% and did not increase again until 1987, when the family planning program was resumed more rigorously. Changes in age at marriage after 1970 (with the exception of 1980 and 1981) resulted in 35.5892 million births averted. After 1970 the decline in fertility accelerated with the increase in years after marriage. Postnuptial fertility was different in rural and urban areas. Multi-child fertility has declined over time. Further declines in the TDFR are possible with the elimination of multibirths. The TDFR of 2.47 in 1988 could be reduced to 1.95, which is about the rate in Jilin and Heilongjiang states during 1986-90. Based on the 1990 census, fertility regions can be grouped five ways. The two highest fertility groups included region IV in the central Chinese states of Hebei, Shanxi, Hubei, Hunan, Shaanxi, Gansu, Anhui, Henan, Jiangxi, Guangdong, and Fujian (47.15% of total Chinese population) and high fertility areas (region V) in southwest and northwest China (areas with large minority populations and lax family planning controls). Fertility has declined since 1987 in region IV. Fertility in region V varies by state and is declining slowly with the exception of Guizhou and Guangxi.