Penn State researcher Dr. Nancy Darling reports 98% of teens reported lying to their parents. They lied about what they spent their allowances on, whether they'd started dating, what clothes they put on away from the house, what movie they went to, who they went with, and more.
Yet 98% of teens say trust and honesty are essential in a personal relationship. Depending on their ages, 96-98% say lying is morally wrong.
The most disturbing reason children lie is that their parents teach them to do so. When adults are asked to keep diaries of their own lies, they admit to about one lie per social interaction, which works out to one per day. Parental modeling leads children to gradually get comfortable with being disingenuous.
Source: New York Magazine, 2/10/08, cited in the AACC Journal.