Japanese fertility has been decreasing since 1973 due to changes in age structure and marital patterns, rather than marital fertility. The average number of children per family has remained stable, with most young couples wanting 2-3 children. The delay in marriage is caused by imbalanced sex ratios and increased college enrollment rates, but this trend is expected to end soon. Despite the decline in marriage rates, most unmarried individuals still plan to marry in their late 20s. As a result, there may be an increase in married women aged 25-34, leading to higher birth rates at older ages and potentially an increase in the total fertility rate.