Dr. Kwaku Ohene-Frempong is an avid sports fan. He fondly remembers his days as a track star at Yale.

"I'm supposedly a friend of the NCAA," the University of Pennsylvania professor emeritus said. "I've received awards from the NCAA and I treasure them."

That's why Ohene-Frempong is a little shocked to be speaking up against a recent NCAA policy that requires new athletes be tested for sickle cell trait.

"The NCAA is wrong for this whole thing," he said. "They may have thought this was something good that they were going to do, but they went about it in the wrong way."

Ohene-Frempong admits the reasons he and some other doctors and academics disagree with the NCAA's policy are complicated. It boils down to this: they don't think sickle cell trait can cause sudden death in some people following extreme physical distress as many other doctors believe. They contend signs of the trait don't show up until after death and the underlying causes are being ignored.

They are against athlete testing because they think it robs attention from the real causes of death, such as heat stroke and cardiac arrest. They also worry that athletes who test positive for the trait might be discriminated against.

And they believe blaming the deaths on sickle cell trait lets schools and coaches off the hook too easy.

"These are young people who have been playing sports most of their lives," he said. "And if people like that walk on your field and get injured in a way that you could not have predicted, you first need to look at your field and say, 'What are we doing to these young people? … What did we do so that they came here and they died?'"

The debate

Sickle cell anemia is a painful disease that attacks a person's red blood cells. The cells are normally round and flexible, but they often become sickled and rigid. The cells get sticky and can clog blood vessels, depriving the body of oxygen. Sickle cell anemia can cause strokes, severe organ damage and shortens a person's life span.

While sickle cell anemia is a crippling condition that is impossible to ignore, the majority of people with sickle cell trait never have any symptoms or health problems related to the trait. A person with sickle cell trait has normal red blood cells. However, many doctors believe under extreme physical stress, the trait can cause a carrier's red blood cells to collapse, quickly break down muscle tissue and shut down vital organs.

Since 2000, nine college football deaths have been blamed on sickle cell trait complications, including the 2008 death of UCF freshman wide receiver Ereck Plancher.

Last April, the NCAA handed down guidelines requiring its Division I schools screen new athletes for sickle cell trait unless they can prove they have previously been tested or sign a waiver declining to be tested. The guidelines came in the wake of a lawsuit filed by the family of former Rice University football player Dale Lloyd II, who died after a workout in 2006.

The NCAA's decision has caused some controversy.

Lack of oxygen causes red blood cells to collapse, or sickle. After a person dies, oxygen stops flowing through the body and blood cells naturally sickle. Some doctors argue deaths that have been tied to sickle cell trait are a misdiagnosis of a change in the body that occurred after death.

"As soon as you're not getting oxygen into your blood anymore, you're going to sickle," University of Miami cardiologist Robert Myerburg said. "That's something that happens after death."

However, some pathologists argue they see a dramatically increased number of sickled red blood cells in people whose deaths are linked to the trait. A 2005 article published in the Wisconsin Medical Journal discusses a patient whose oxygen levels were controlled during surgery. A tissue sample was taken from the patient and showed sickled red blood cells.

Jon Thogmartin, the Pasco and Pinellas chief medical examiner, co-wrote a case report in the 2011 Journal of Forensic Sciences arguing sickle cell trait contributed to the death of 16 individuals. He argues there are a long list of signs besides warped blood cells that have helped him tie the deaths to sickle cell trait.

"It's magical thinking to say these deaths are not related to sickle cell trait," Thogmartin said.