Later marriages
Nature
With greater financial and social independence, women are marrying later in life. A single working woman may want to get married, but is in less of a rush and more selective about her mate. To a lesser degree this applies to men also, but the net result is that many men are having difficulty finding a marriageable wife. Women are also bearing their first child at a later age on average, sometimes well into their 40s.
Incidence
The average age for marrying Japanese women rose from 24.4 in 1980 to 25.9 in 1990. The corresponding rise for Japanese men was 27.2 to 28.4.