Definition: In this task, you are given a text of many news articles seperated by special token "|||||". Your task is to summarize them.
Input: Nearly one in five American women in her early 40s is childless, according to a report that shows a striking increase in women who don't have biological children. 
  
 The trend was much less common in the 1970s, when one in 10 women did not have children by 40 to 44, the age bracket researchers use to designate the end of childbearing years. 
  
 The report, released Friday by the Pew Research Center, cites social and cultural shifts behind the change, including less pressure to have children, better contraceptive measures and expanded job opportunities for women. 
  
 "I certainly think it's notable that there is such a large increase in the share of women who do not have children for whatever reasons," said D'Vera Cohn, a coauthor of the study. She said that some women were childless by choice; others wanted children but could not have them. A "very, very small number" would go on to have children, she said. 
  
 "The fact that nearly one of five women does not have a child of her own -- that's an enormous transformation from the past," Cohn said. 
  
 Although the trend largely held true across races, ethnicities and education levels, one exception was among women with advanced degrees -- a master's or higher -- who were more likely to give birth. In 1994, 31 percent were childless in their 40s. In 2008, 24 percent were. 
  
 This may reflect a growing belief that women can have both a career and a family, said Tanya Koropeckyj-Cox, a sociologist at the University of Florida. She that in the 1990s, "it was more difficult to try to do both, and now there is a cultural shift that has made it more feasible to have a career while still also having a family." 
  
 She also said that professional women often have more resources to take advantage of infertility treatments. 
  
 The Pew report shows that the shift was opposite for women with less than a high school diploma. In 1994, 9 percent of that group was childless. In 2008, that figure was 15 percent -- an increase of 66 percent, says the report, which notes general trends in delaying marriage and childbearing. 
  
 Overall, the report found that white women are more likely to be childless, as are women with more education. The analysis, based largely on census data, comes amid changing attitudes about women who do not have children. 
  
 In 1988, 39 percent of those interviewed as part of the General Social Survey said they didn't think people without children "lead empty lives." By 2002, that figure was 59 percent. 
  
 The number of women without biological children is much larger than it once was, with 1.9 million childless women in 2008, compared with 580,000 in 1976. 
  
 The Pew study explored biological childbearing and did not touch on whether women had adopted children or stepchildren. 
  
 Childless women are as happy as women who had children at typical ages, said Amy Pienta, a researcher at the University of Michigan who coauthored a study on the subject. "They are not any more depressed; their psychological well-being is just as high," she said. ||||| 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. 
  
 Other findings: 
  
 _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. 
  
 ___ 
  
 Online: 
  
 http://pewresearch.org/ |||||
Output:
The percentage of American women who enter their 40s having never had a child has almost doubled since the 1970s to 18%, according to a Pew Research Center analysis of census data. White women are more likely than ethnic minorities to remain childless, though the gap is rapidly narrowing, the AP reports: Childlessness among Hispanics and African-Americans grew three times faster than childlessness among whites in the 1990s. The researchers say social pressure to have children has eased and remaining childless is now seen as an individual choice. And while better-educated women are less likely to have children, the study found that women with a master's degree or higher are likelier to have children now than they were in the early '90s (24% of women age 40-44 were childless in 2008, compared to 31% in 1994). Since the '90s there has been "a cultural shift that has made it more feasible to have a career while still also having a family," a University of Florida sociologist tells the Washington Post.