Thanks to the reader who sent us this story.

There's no doubt that you've heard about the stories regarding Steelers defensive back Ryan Clark, who has been benched multiple times when Pittsburgh plays the Broncos in Denver. The reason for it is a Sickle Cell trait, in which "red blood cells form an abnormal sickle or crescent shape." And since the air is thinner in Denver, there's a certain risk.

Tuesday, June 19th, marks World Sickle Cell Awareness Day.

Though Clark is often the most publicized story, Bengals defensive tackle Geno Atkins, who also has the trait, shares his story.

"Once I learned I had the trait I researched as much as I could and talked with the football training staff. They assured me that the trait would not affect my ability to play. There were four freshmen who tested positive for the trait along with me and we were assigned a trainer who watched us closely during practice sessions and on game day. I was not treated differently by my teammates and went about my life just as I had before. One day I learned that a football player had died from complications of sickle cell trait while participating in spring practice at another university. That's when I realized that this is a serious issue and I should not take any chances with my health. I played at the highest level in college and it earned me a spot in the NFL."

You can read it all here.