Parents now have another reason to question whether their young children should be playing tackle football.

A recent study found that children under age 12 who play the contact sport are more likely to suffer from depression, apathy, and other behavioral issues when they are older, the national health publication STAT reported.

The findings raise more concerns in a sport already dealing with declining participation as parents assess the risk of concussions.

The study, which appeared in the current issue of Nature's Translational Psychiatry, included 214 men who were age 51 or older. About half started playing football before age 12 and the rest at 12 or older. Forty-three of them played through high school and 103 played through college. The remainder played professionally.

Participants who played youth football had a twofold increase in risk for apathy and behavioral regulation and a threefold increase in risk for depression, compared with those who started playing later, the study reported.

Age 12 was used as a cutoff because the brain experiences a key period of development between 10 and 12, researchers stated.

Study author Robert Stern, the director of clinical research at Boston University's CTE Center, told STAT the research has "tons of limitations." The participants were not chosen at random and they were interviewed by phone and completed online questionnaires and not interviewed in person.

The data are not strong enough to point to football as the cause of behavioral abnormalities in young adults, but the findings provide another reason to question whether children should participate in the game, Stern stated.

"When do we ask ourselves, 'Does it make sense for my kid to be hitting his head several hundred times per season?' " Stern told STAT.

In recent seasons, youth organizations such as Pop Warner and USA Football have implemented or tested significant rules changes, STAT reported. And proponents of youth football point out the benefits of physical exercise, teamwork, discipline, and camaraderie that the game offers.

However, Stern points out that football is not the only team sport available for children to play, the story reported.