Of the many facts we will never learn regarding the Newtown shootings, one is the mindset of Nancy Lanza.

This handout image provided by ABC News, shows Nancy J. Lanza, mother of suspected mass shooter Adam Lanza at an unspecified time and place. (Handout/Getty Images)

If so, hers would have been an extreme form of what, it turns out, is an affliction suffered by most parents.

Last month, the University of Virginia’s Institute for Advanced Studies in Culture released survey results assessing the “Culture of American Families.” One of the results, based on interviews with thousands of parents nationwide, was that parents often delude themselves when it comes to their own children’s behavior.

For instance:

● Based upon parental reports, the average grade point average for high school students is between 3.15 and 3.24.Yet, according to national transcript data, the average high school grade point average is between 2.95 and 3.0.

● Based upon reports from parents of teenagers, only one in 10 children ever drinks alcohol. Yet, according to the U.S. Centers for Disease Control and Prevention, 72 percent of all high school students report having tried alcohol and 42 percent of them in the last 30 days.

● Based upon parental reports, only about 17 percent of high school students are sexually active and 60 percent of have “definitely not” experienced sexual intercourse.

Yet, according to the CDC, 42 percent of all high school boys and 43 percent of all high school girls report having sex.

At the same time, another recent study by the Family Online Safety Institute revealed wide gaps between parental perceptions of their teen’s online usage and the teen’s own perceptions.

For instance, more than 90 percent of parents reported that they were well-informed about their teens’ online and cell phone activity.

Only about 20 percent of teens agreed.

“It may be that the biggest barrier to intervention with troubled kids or kids engaged in high-risk behavior is their parents,” researchers concluded in a commentary accompanying the Culture of American Families survey.

“Parents worry about all sorts of challenges to their children’s development and vitality, but they have difficulty admitting to their children’s problems, preferring more optimistic assessments of their own family.”

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