Births and Age

Nearly 1.5 million babies, a record, were born to unmarried women in the United States last year.

But teens accounted for just 24 percent of unwed births, down from 50 percent in 1970.

The increases in unmarried births have been among women in their 20s, especially those 25 to 29. Many are living with partners but still count as unmarried mothers if they haven’t formally married.

The 20s are the prime childbearing years, regardless of whether the mother is married or not. Among teens, more than 80 percent of mothers were unmarried.

There were 1,470,152 babies born to single women in 2004, 35.7 percent of all births up from 1,415,995 a year earlier.

The birth rate for women aged 35 to 39 increased 4 percent from 2003 to 2004. It was up 3 percent for women aged 40 to 44 and 9 percent for those 45 to 49.