We are aware that testosterone, the male hormone, is responsible for all things male and macho, adding to aggression and spirit of competition.

During the study, some participants were treated with testosterone in the form of a gel by applying it to their skin. Other participants were given a placebo gel. The study involved games which tempted them to cheat- playing a game of dice in separate booths and putting up their own score on a computer.
The study revealed that those given the testosterone gel showed lesser likelihood of cheating, even when tempted, than the men who were given the placebo.
This study led researchers to believe that the hormone enhances honesty in men and the desire to portray a positive image.
Source-Medindia