Cindy Parlow helped the United States win two Olympic gold medals and a World Cup in soccer, and she was particularly skilled at heading the ball. Now she is paying for those repeated thumps on the head. As she tells Mary Carillo of HBO's Real Sports, Parlow began phasing out headers at the end of her career.

"Every time I headed the ball I would see stars," she says. "I was having a lot of headaches, a lot of jaw pain, a lot of fatigue."

Carillo asks how long the symptoms lasted.

"They've never gone away," Parlow says.

This is why Parlow, who retired in 2006, and Brandi Chastain are among the most influential voices calling for a ban of heading for players under 14. Soccer ranks second behind football in concussions sustained by the athletes, and the brains of youngsters are especially vulnerable because they are still developing. Here's a part of the Real Sports segment that premieres Tuesday at 10 p.m. ET/PT:

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