Breast-feeding babies may provide children with an academic advantage later in life, according to a new study.

Infants breast-fed for at least six months after birth scored higher on math, reading and spelling tests at age 10 than those breast-fed for less than six months, the researchers said. The benefit was particularly pronounced in boys.

The results held even after the researchers took into account factors that may have influenced test scores, including the mother's educational level, family income and whether or not the children had stories read to them when they were younger.

The boost in test scores may be due to specific nutrients in breast milk, said study researcher Wendy Oddy, of the Telethon Institute for Child Health Research in Perth, Australia. Breast milk contains certain fatty acids that aid in brain growth and development, she said.

The study is published in the January issue of the journal Pediatrics.

While previous studies have suggested breast-fed infants do better on tests of cognition and IQ, it has not been clear whether these advantages result from nutrients in the milk or other factors, such as higher socioeconomic status. In addition, few studies have looked to see whether breast-feeding affects boys and girls differently.

Oddy and her colleagues examined the test scores of 1,038 Australian children who had been part of a study since before they were born.

At age 10, boys who had been breast-fed for at least six months scored about 10 percent better on standardized math tests, and about 7 percent better on spelling tests, than those breast-fed for less than six months, Oddy said.

There was little difference in test scores between girls who were breast-fed and those who were not.

However, this result does not mean that breast-feeding isn't important for girls, Oddy said, because the finding in boys shows that it likely still benefits brain development.

But girls and boys develop differently, and breast-feeding may have a stronger impact on brain development  in boys than girls, Oddy said.

In addition, girls have more of the hormone estrogen, which has been shown to be protective of the brain as it develops, Oddy said.

The researchers noted the parents of children in the study — who had allowed the researchers to analyze their children's medical information and tests scores — were more likely to breast-feed their children and have higher incomes than parents. So the results do not necessarily apply to the population as a whole.

The study was funded by the National Health and Medical Research Council of Australia, the Australian Rotary Health Research Fund, among others.

Pass it on: Babies breast-fed for six months, particularly boys, may perform better on academic tests later in life than those breast-fed for a shorter time.

Follow MyHealthNewsDaily staff writer Rachael Rettner on Twitter @Rachael_MHND.