Nearly 1 in 5 American women beyond childbearing years never gave birth as fewer couples, particularly higher-educated whites, view having children as necessary to a good marriage.
An analysis of census data by the Pew Research Center, being released Friday, documents the changes in fertility rates that are driving government projections that U.S. minorities will become the majority by midcentury.
The figures show that among all women ages 40-44, about 18 percent, or 1.9 million, were childless in 2008. That's up from 10 percent, or nearly 580,000 in 1976.
Broken down by race, roughly 20 percent of white women are childless, compared with 17 percent of blacks and of Hispanics and 16 percent of Asians. Still that gap has been narrowing: Since 1994, childlessness for blacks and Hispanics has grown by 30 percent, about three times the rate for whites.
The numbers coincide with broader U.S. trends of delayed marriage and increased opportunities for women, who now outnumber men in the work force and have drawn even with them in advanced degrees. After reaching a high of 3.7 children per woman during the baby boom, the U.S. fertility rate dropped to a historic low of 1.7 during the mid-1970s and stands at about 2.
The findings also come amid a historic demographic shift in which blacks, Hispanics, Asians and multiracial people are growing rapidly in the U.S. population and wielding more influence in politics and society. Minority babies now make up nearly half of all U.S. births.
"Social pressure to bear children appears to have diminished for women and that today, the decision to have a child is seen as an individual choice," according to the report by Pew researchers Gretchen Livingston and D'Vera Cohn. "Improved opportunities and contraceptive methods help create alternatives for women."
While higher-educated women overall are more likely to be childless, that may be slowly changing. In 2008, about 24 percent of women ages 40-44 with a master's, doctoral or professional degree did not have children, a decline from 31 percent in 1994.
In the meantime, childlessness has risen sharply for women with less than a high school diploma — from 9 percent in 1994 to 15 percent in 2008.
— Less than half, or 41 percent, of surveyed Americans said that children were very important for a successful marriage. Still, a rising share of people — about 38 percent in 2009 — say the trend of increased childlessness is bad for society.
— More births are from women who never married. Among never-married women ages 40-44, about 56 percent were childless in 2008 compared with 71 percent in 1994.
— U.S. childless rates were somewhat similar, if not higher, compared with other industrialized nations. About 17 percent of U.S. women were childless at age 40, compared to 22 percent in England, and 17 percent in Italy and Ireland. The rates were between 12 percent and 14 percent for Spain, Norway, Denmark, Belgium and Sweden.
Pew, an independent research group, based its findings on 2008 data from the Census Bureau. The report analyzes the population of women who do not have biological children, as opposed to adoptive or stepchildren. Figures for "white" refer to those whites who are not of Hispanic ethnicity.