Recent studies indicated that cooking ground beef well-done can increase the risk of developing prostate cancer. Researchers discovered that men who regularly consumed well-done meat had a 50% higher risk of developing prostate cancer when compared to those who consumed rare to medium cooked beef. John Witte, PH.D., a professor at the University of California at San Francisco states that cooking meat well can create chemical compounds that have been linked to cancer.
In short, eat your beef rare-medium. Be on the safe side.
Never cook your meat above 160 degrees Fahrenheit.