Former Tottenham midfielder Ryan Mason has called for a ban on children heading footballs.
Mason, 27, retired from football in February last year after he fractured his skull while playing for Hull City against Chelsea in January 2017.
"If you have got a seven or eight-year-old heading a solid ball, and his brain and his bone in his skull isn't fully developed, that could potentially be doing damage," Mason, capped once by England, told BBC London.
"I look at some kids and they head the ball with the top of the head and their technique is all wrong, therefore the pressure that it's putting on the brain is a lot more.
"I don't think kids should be heading real balls."
In the United States, under-11s are banned from heading by the U.S. Soccer Federation, while there are also limitations for 11 to 13-year-olds.
"America is probably more advanced than England in terms of research, and they've taken the measure of actually banning it up to a certain age. So maybe we can follow those footsteps over here to protect our young kids," Mason said.
The Professional Footballers' Association has campaigned for restrictions on heading and Mason added: "Maybe bring in sponge balls to learn the technique and gain that experience of actually challenging for a header.
"I don't think repetitive heading at a young age is doing the kids any good, that's for sure."