In measuring a child's chance for success, researchers at Brigham Young, Johns Hopkins, and Columbia Universities have found that a mother's age at the birth of her child--even after accounting for other characteristics such as poverty, education, and marital status--is a definite factor on its own.
Researchers found, in a study that began more than 30 years ago, that children of inner-city mothers who were 25 years or older at the time of their children's births had the most favorable adult outcomes. In comparison, children of teenage inner-city mothers had the least favorable adult outcomes, even after controlling for other variables. The results were reported in Pediatrics, the journal of the American Academy of Pediatrics.
Researchers designated three areas as indicators of children's success: achievement of a high school diploma, financial independence of public support, and delay of having the first child until age 20 or older.
BYU's Sterling Hilton, assistant professor of statistics, handled the statistical analysis of data gathered by the Johns Hopkins research team. The tracking of these children is significant because few studies on the impact of teenage childbirth have included follow-up reports when the children reach adulthood, said Hilton. Also, few include the children of older mothers for comparison.
Janet Hardy of Johns Hopkins' School of Medicine spearheaded the effort to understand the impact of maternal age. "Society is concerned about the problems that young motherhood brings, but it also glamorizes youth," Hardy says. She speculates that "older mothers are better parents because they are more mature socially." The study also indicates that they are also more likely to have adequate resources.
The legwork for the findings has spanned four decades. Hardy began an initial study in the 1960s to track the progress of inner-city children from birth. Her team interviewed more than 2,000 inner-city mothers when they were pregnant and again when their children reached age 8. Decades later, while moving offices, she was confronted with the 60 five-drawer file cabinets that held that data.
"I started wondering if there would be any value in going back and seeing what has happened to these people," she says.
Hardy decided the research could fill a niche in the study of metropolitan areas. "Much has been written about the structural changes in large cities, but very few people have had a population of people to go hand in hand with the structural study," she says.
To reconstruct such a population for study, Hardy's colleagues combed hospital records, traced next of kin, and even scoured motor vehicle registry records looking for the offspring of those mothers interviewed 25 to 30 years earlier.
The team succeeded in locating and interviewing 1,758, or 71 percent, of the children in the initial study, who in the latest round of interviews were in their late 20s to early 30s.
The interviewers found the children as far flung as Germany and California. Some own businesses and earn as much as $250,000 a year. Others call home a Baltimore street corner or jail cell. One, who declined to participate, plays in the NBA.
Hilton first compared the adult outcomes of children born to mothers younger than 20 to those born to mothers aged 2024. After controlling for other variables--such as poverty, education, and marital status of the mothers, as well as race and gender of the child--he found that children of teenage moms were less likely to achieve success in the three areas outlined than those born to mothers in their early 20s. Using the same methods, he found that children born to mothers 25 and older were more likely to succeed than those born to mothers in their early 20s.
Hilton, who met Hardy while completing his doctorate in biostatistics at Johns Hopkins, suggests that the results of the study can be used by policy makers and planners interested in population trends. However, he cautions against using studies about groups of people to predict individual outcomes.
While children of older mothers were less likely to become teenage parents when compared to children of teenage mothers, Hilton hopes the study will not "contribute to the fallacy that children of teenage moms will inevitably become teenage parents themselves." He points out that 68 percent of the children born to teenage mothers did not have children before they reached age 20.
Hilton also warned against the mentality that children of teenage mothers are "doomed" to failure. The study shows that, of all children born to mothers less than 20 years old, 62 percent received their high school diploma and 72 percent were financially independent of public support.
The impact of maternal age at birth is the first of many areas that researchers will explore with the rich longitudinal data set. Hardy says blood serum samples taken from the mothers during pregnancy can be used to link health events during pregnancy with outcomes--such as asthma or heart disease--later in children's lives. In another effort, study co-author Therese Miller is looking at factors that influence the age of the onset of sexual activity. Hardy also leaves the door open for further interviews with the "children" in years to come.
Hardy, Hilton, and Miller were joined as study co-authors by Sam Shapiro and Nan Astone of Johns Hopkins and Jeanne Brooks-Gunn of Columbia University.