A specification of marital fertility by parents' age, age at marriage and marital duration.

The positive association between wife's age at marriage and fertility experienced at the older reproductive ages, cited in recent natural fertility literature, is explored using Mormon birth cohorts from 1840 to 1879. When this relationship is specified by husband's age at marriage and marriage duration, the results indicate that older-aged husbands depress marital fertility only at higher marriage durations. The general decomposition of age-specific fertility utilizing both mother's and father's age is also considered. The results show that mother's aging is the most important factor, while father's aging has a moderately negative effect under a natural fertility regime.