It's funny how one story and one man's opinion can have parents worried they signed away their child's mental health for the sake of a Saturday morning winter sport.

Ever since the New Zealand Herald's Dylan Cleaver released a comprehensive story and an informed opinion piece two weeks ago on studies into American football players and the difference between those who had played the sport before the age of 12 and those who hadn't, it has got more than one Northland parent wondering if they made the right call by their child.

The research, conducted in the United States, broadly