Good news for women who are worried about waiting until after age 30 to become moms: It might have a positive effect on your future child's intelligence level.

According to a recently resurfaced set of data from the journal Biodemography and Social Biology, kids born to mothers who were 30 to 39 years old when they gave birth generally scored higher on cognitive tests at age 5 when compared to their counterparts — children born to moms who were 23 to 29 years old.

Conducted by researchers at the London School of Economics and published in December 2015, the study looked at 18,000 children who were enrolled in the Millennium Cohort Study to reach its conclusions.

As researcher Alice Goisis said, according to U.K. outlet The Times, "First-time mothers in their 30s are, for example, likely to be more educated, have higher incomes, are more likely to be in stable relationships, have healthier lifestyles, seek prenatal care earlier and have planned their pregnancies."

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Interestingly, researchers did not observe the same effect for children born to women over 40 — meaning there was seemingly no higher cognitive ability in kids with mothers who were older than 40 when they gave birth.

However, they did see a rise in prevalence of obesity in children from this age group of moms, potentially tied to findings showing moms over age 40 were less likely to engage in physical play with their kids.

It's important to note that only 53 moms were included in the 40-or-older portion of the study, though, according to The Independent.


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According to The Independent, women who become moms at a later age are more likely to breastfeed and read to their kids, while the chance that they are smokers is lower than that of younger moms.

The average age of first-time moms in the United States is 26, The New York Times reported in August — a jump of five years since 1972. For dads, that number rose from 27 to 31 since 1972.

This Story Originally Appeared On People