After Dr. Elizabeth King was finished with her treatment—double mastectomy, chemotherapy, stem cell mobilization and reinfusion, and radiation—she sat outside her Atlanta home and watched her eight-year-old son, Mitchell, skate in the driveway. After more than nine months of dangerous and debilitating treatment for breast cancer, she enjoyed just feeling the sun on her face as her son showed off some new moves.

The conversation turned to Mitchell's request to play football in the fall. Given the injury rate in the sport, King and Mitchell's father were not keen on the idea. Mitchell skated over and sat down beside her.

"He looks at me and says, 'You know, I think I'm going to play football,'" King recalls. "'I want to scare you as much as you scared me.'"