Despite it probably being near the top of the “I Would Never" list for parenting, it turns out the overwhelming majority of us do play favorites with children—and it's especially obvious if you have both boys and girls.

A study forthcoming in the Journal of Consumer Psychology found moms favor daughters while dads favor sons when it comes to both time and money spent on the children.

The researchers suggest this display of preference is because we're unwittingly prone to spoil children of our same sex due to the closer shared-experience connections (And we may even want to vicariously relive our childhoods with bigger advantages.)

In the study of American and Indian parents who had both a son and daughter, researchers asked the adults to decide which child should receive a treasury bond, more money in their wills or the chance to win a back-to-school prize package. In each case, dads felt more generous toward sons and moms gave more to the daughters. In the example of the back-to-school prizes, 76% of women favored the girls while 87% of the men favored the boys.

It may not seem like a big deal when it comes to more pencils and notepaper for school, but the broader implications are significant, says the study's co-author Lambrianos Nikiforidis, an assistant professor of marketing at the State University of New York, Oneonta.

“For example, when men control the family's financial decisions, then sons may chronically receive more resources than daughters. By contrast, if women are the primary shoppers, this can result in subtle but consistent favoritism for daughters," explains Nikiforidis, adding the sex-matching bias may be even more troublesome in same-sex or single-parent households where there is no balance for the favoritism.

Next, the researchers plan to investigate how the bias may affect people in positions of power such as politicians or corporate leaders. If the trend continues as suspected, the researchers say this may explain a great deal about why many programs and policies favor men.

In the meantime, for those of us in household positions of power, this is a good reminder to be aware of the ways we may unintentionally favor one child over another—and why you should just look into splitting that treasury bond money straight down the middle.