These variables mainly include those which are related to the formation and dissolution of families through marriage, though pre-marital sexual practices may also be included in this group. In most societies, sexual intercourse and child-bearing are permitted only to married couples.

The variables which determine the formation and dissolution of marital unions, therefore, gain in importance in this context.

These include age at marriage, proportion of females who married proportion of widows and the extent of widow remarriages, divorces, and remarriages of the divorced. These are variables which affect the first stage of the process of child-bearing that is sexual intercourse.

Among the various variables determining the formation and dissolution of marital unions, the female age at marriage and the proportion of those who never married in the reproductive age group are important, in the sense that they have a major share in determining fertility levels and differentials.


In pre-industrial societies, the age at marriage is generally very low and early and prolific child-bearing is encouraged. This is supposed to be a functional response to the high mortality levels prevailing in that society.

The female age at marriage and its effect on societal fertility is much-investigated topic in the field of demography.

In high- fertility societies, where the practice of contraception is almost non-existent, the duration of the period spent in the reproductive ages (as a concomitant of the age at marriage) acquires importance in its effect on fertility.

The lower level of European fertility prior to the Industrial Revolution has been partly attributed to the higher female age at marriage, and the higher proportion of never-married women. Kingsley Davis has argued that the postponement of marriage, and not celibacy, was one of the many ways in which Japan attempted to bring about a reduction in her fertility rates.


In India; several studies have been conducted to estimate the effects of the higher female age at marriage on fertility. Agarwala has pointed out that if all Indian women get married after the age of 19, there would be a 30 per cent reduction in the birth rate by 1991-1992.

It was found in 1966 survey of fertility and family planning in Greater Bombay that those women who married before the age of 19 had, on an average, one child more than those who married after the age of 19.

In Ireland, the marriage pattern is unique, in the sense that the proportion of females, who have not married up to the age of 45, is usually high, so is the female age at marriage.

In fact, Ireland is the only country in the world where the marriage pattern is according to the Malthusian dictates, with the result that Irish fertility is low.