A forensic scientist has testified that two cotton balls and a syringe needle allegedly saved after a steroids injection tested positive for Roger Clemens' DNA - in a key moment as the government tries to prove the former pitcher used performance-enhancing drugs.
Alan Keel told jurors Friday that the DNA on both cotton ball matches were ''unique to one person who has ever lived on the planet'' - Clemens. He said that one cotton ball had a random match possibility of 1 in 15.4 trillion for Clemens' DNA, and the other had one in 173 trillion.
The needle was not as conclusive, because Keel was only able to get a handful of cells. That match was one in 449.
Brian McNamee, Clemens' former strength coach, earlier testified he collected the medical waste after injecting the pitcher with steroids.
Clemens is accused of lying to Congress when he denied using performance-enhancing drugs.