Babies who are suckled by their mothers for at least four months are less likely to grow into children with behavioral problems by the time they reach 5 years old, according to a study published in the Archives of Disease in Childhood and reported by Reuters.

Breast-feeding benefits for mother and child are well-known. They include lowered infection rates for breast-fed babies and a reduced breast cancer risk for the moms. And while previous research suggested breast feeding may offer child development benefits, this is the first study to show consistent evidence.

For the study, researchers from the universities of Oxford, Essex and York and the University College London used a nationwide British survey of babies born between 2000 and 2001. The survey included more than 9,500 mothers and babies.

Next, scientists collected data about how long mothers breast-fed their babies and how parents scored the “strengths and difficulties” of their children.

Researchers found that only 6 percent of breast-fed children showed scores indicating they might have potential behavioral problems compared with 16 percent of formula-fed children. What’s more, breast-fed children still showed a decreased chance of developing behavioral problems, even when scientists factored in other circumstances, such as socioeconomic and parental influences.

“Mothers who want to breast-feed should be given all the support they need,” said Maria Quigley, a doctor from the national perinatal epidemiology unit at Oxford University. “Many women struggle to breast-feed for as long as they might otherwise like, and many don’t receive the support that might make a difference.”

Children who are not breast-fed may experience a host of mild behavioral problems, such as anxiousness, restlessness or inability to play with other children or socialize. Why? Experts believe they miss getting large amounts of a specific fatty acid, growth factors, and hormones found in breast milk, which are crucial for brain and nervous system development.

In addition, breast-feeding also increases mother-and-child interaction, which helps kids better learn acceptable behaviors.

Click here to learn how breast-feeding affects your child’s academic performance in school.