Yes actually, I would believe a scientist with years of experience in gathering objective data and interpreting research based on the observed behaviour of thousands of teenagers and their eventual development into adulthood. At the very least, I would trust his expertise far more than the defensive opinion of a single teenager and a handful of friends, all themselves still mired in adolescence and thusly unable to provide truly objective, retrospective feedback as to the actual motives for their day to day activities and reactiions to stress as teenagers (as none of us are particularly good at explaining our motives in the moment, and become defensive at the insight of others.)

In short, tell me your thoughts once you're on the other side of all that he's talking about.

This is not to say everything Dr. Sax says is correct; however, while he may not represent every teenage girl out there, he has a lot more valuable insight from direct experience with adolecents than many of us could ever hope to attain. As with any media, this should be taken with appropriate constructive criticism, but these in depth observations are certainly worth consideration, debate and discussion.