Cheaters Drawn to the Opportunity to Cheat

The article states, "Among the participants in the study, 50 percent refrained from cheating entirely in the experiment; around 30 percent did not hesitate to lie at all, and around 20 percent of the subjects, who had actually opted for more honest earning opportunities, nevertheless seized the opportunity to cheat when it presented itself."

This makes me wonder -- Do we live in a world in which 50% of the human population is inherently dishonest? Regardless of the actual percentages, I also wonder to what extent a predisposition for dishonesty may be heritable.