Past research has indicated that friends can influence each other in certain behaviors, such as smoking, drinking and exercising. Now, new research suggests such influence stretches as far as fertility decisions. A study published in the American Sociological Review finds that, among female high school friends, having children is contagious during early adulthood.
The research team, including Nicoletta Balbo, a postdoctoral fellow at Bocconi University in Italy, notes that previous studies have found that a woman’s fertility choices may be influenced by relatives and work colleagues. But they say their study is the first to demonstrate such an influence among friends.
To reach their findings, the investigators assessed data from more than 1,700 women who were a part of the National Longitudinal Study of Adolescent Health in the US. The women were monitored for approximately 15 years, from the age of 15 to 30.
On looking at the rate of planned pregnancies among high school friends, the team found that when one friend gave birth, other friends immediately thought about having children of their own.
“The study shows the contagion is particularly strong within a short window of time. It increases immediately after a high school friend gives birth, reaches a peak about 2 years later, and then decreases, becoming negligible in the long-run,” explains Balbo.
Study co-author Nicola Barban, a postdoctoral fellow at the University of Groningen in the Netherlands, says this finding makes sense. She explains that the desire to have a child increases over time, and the findings account for a “natural period” prior to conception. “As a result,” she adds, “the effect of a friend giving birth is not immediate.”
Commenting on the findings overall, Balbo says:
“This research demonstrates that fertility decisions are not only influenced by individual characteristics and preferences, but also by the social network in which individuals are embedded. In addition, it shows that high school friends impact our lives well after graduation.”
On average, women in the study gave birth to their first child around 27 years of age.
Explaining the potential reasons behind their findings, Balbo says that people tend to draw comparisons between themselves and their friends, and being surrounded by friends who are new parents puts pressure on those within their social circle to have children, too.
Balbo says that people also tend to observe friends who are new parents, effectively using them as a learning source for when they have children of their own.
In addition, she explains that having children at the same time as friends can pose many benefits.
“Friends can share the childbearing experience and thus reduce the stresses associated with pregnancy and childrearing,” she adds. “It’s also easier for people to remain friends when they are experiencing parenthood at the same time.”
In 2012, Medical News Today reported on a study by researchers at Loyola University in Chicago, IL, which suggested that friends may influence our weight. The researchers found that participants were more likely to gain weight if their friends were heavier. If their friends were leaner, they were more likely to lose weight or gain weight at a slower pace.