This chapter deals with the first two of them: age and proportion married. Age composition and proportions married comprise the first set of intermediate fertility variables identified by John Bongaarts. The sex composition of a population has important effects on marriage composition and consequently on birth rates. A more systematic procedure for examining demographic aspects of the female population requires, first of all, that we decompose the age dimension into more sensitive measurement units. As with age composition, the proportion married is asymmetrically distributed across broad components of the female population. The 1970-1977 birth rate decline must be attributed to other causes, among which marital composition is a prime candidate for consideration. The impact of the differences may be assessed by determining the effect of standardization for marital composition on the total fertility rates measured in 1973 and 1978. Standardized for marital composition, this difference is reduced to 1.37.