The names of NFL players tormented by the degenerative brain disease CTE are well-known: Dave Duerson, Mike Webster, Junior Seau, to name a few. Parents would be smart to familiarize themselves with another name linked with chronic traumatic encephalopathy: Zac Easter.

Zac began playing organized football when he was 8 and didn’t stop until his senior year of high school in Indianola, Iowa. Concussions marred his days as a linebacker. After he stopped playing, Zac coped with depression, headaches and slurred speech. At 24, he took a shotgun from his father’s truck, drove to a state park and blasted a hole into his chest. A postmortem examination of Zac’s brain confirmed what the young man had long suspected: He suffered from CTE.

The degenerative disease is back in the news, thanks to a study led by Ann McKee, director of Boston University’s CTE Center. McKee and her team examined the brains of 111 deceased NFL players and found that all but one had CTE, which is associated with head trauma and linked to symptoms that include depression, dementia and memory loss. McKee also found CTE in three of 14 deceased former high school football players and 48 of 53 deceased former players at the college level.

Last year, 3 million kids ages 6 to 18 played organized football in the U.S. McKee’s findings should give their parents a reason to stop and think: Given what we know now about CTE, does tackle football still make sense for their kids?

Organizers of youth football leagues, as well as administrators of schools with football programs, should ask the same question. Growing concerns about liability should be part of that calculation. America’s largest youth football league, Pop Warner, settled a $5 million lawsuit in 2016 with the family of a former player from Wisconsin who joined the league at 11 and played for four years. He killed himself at 25, and an examination of his brain revealed CTE.

But it’s not primarily a money issue. Consider the science behind CTE. Repeated blows to the head cause the buildup of an abnormal protein that degenerates brain tissue. Areas of the brain vulnerable to CTE include those that govern cognition, working memory, abstract reasoning, planning, emotional control and aggression. CTE also has been linked to the onset of ALS, or Lou Gehrig’s disease, later in life.

Youth leagues and high schools have reacted with a bevy of safety measures, from scaling back the amount of contact in practices to teaching safe tackling and blocking techniques. Whether those measures will be enough remains to be seen.

CTE researchers have amassed a formidable body of knowledge about the disease and its link to football, but there’s more exploration to do.

The Des Moines Register reported that Zac Easter kept a journal he called “Concussions: My Silent Struggle.” The paper said he shot himself in the chest rather than the head because he wanted his brain examined for evidence of CTE.

“I’m horrified every time an athlete runs out on a field on a Friday night,” Zac’s mother, Brenda Easter, told the Register after learning of McKee’s latest findings. “We don’t know who the next Zac is going to be.”

Parents, as you mull the pros and cons of allowing your children to play tackle football, keep Zac and his mother in mind.