US President Barack Obama said fans of American football must accept that the sport is likely to change rules to reduce the violence and impact on players, including brain injuries.
In an interview with The New Republic made public a week before the Super Bowl gridiron showdown between San Francisco and Baltimore, Obama was asked if he took less pleasure watching the sport knowing the toll it takes on players.
"I'm a big football fan, but I have to tell you, if I had a son, I would have to think long and hard before I let him play football," said Obama, who has two daughters.
"And I think that those of us who love the sport are going to have to wrestle with the fact that it will probably change gradually to try to reduce some of the violence.
"In some cases, that may make it a little bit less exciting, but it will be a whole lot better for the players and those of us who are fans maybe won't have to examine our consciences quite as much."
Concussions have been a major issue for the National Football League, with the long-term impact of blows to the head on players a growing concern.
The family of former NFL star linebacker Junior Seau has filed a wrongful death lawsuit against the league for not doing more to protect players from head injuries, saying the NFL hid the risks of repeated head injuries.
Seau died in May at the age of 43 after shooting himself. Post-mortem tests showed he suffered from chronic traumatic encephalopathy as a result of concussions and other blows to the head taken during his career.
Obama said his major concern was for injuries suffered by players in collegiate American football, in itself a huge US sport that develops NFL talent seeking rich contracts and professional glory.
"I tend to be more worried about college players than NFL players in the sense that the NFL players have a union," Obama said.
"They are grown men. They can make some of these decisions on their own and most of them are well-compensated for the violence they do to their bodies."
The president made it clear he wants the National Collegiate Athletic Association to be concerned about player safety moving forward.
"You read some of these stories about college players who undergo some of these same problems with concussions and so forth and then have nothing to fall back on -- that's something that I would like to see the NCAA think about," he said.