"Teenage atheism is the lack of religion in peoples of the ages 13-19. A great number of teenage people are atheist because of a lack of teachings about God from parents, which many in past generations enjoyed."
My youngest brother became an atheist in his teens because he was sick of the religious crap being shoved down his throat. My other brother, sister, and I followed suit shortly thereafter, even though we were in our 20's by then. Though I tend to lean more towards agnosticism than atheism.
"Another factor may be peer pressure, as modern society has become largely secular and teenage people who profess religion (especially Christianity) are ridiculed, and in cases, bullied."
Funny, most if us who live in the real world find the opposite to be true.
"Yet another factor may be the teaching of evolution as fact in public schools."
For most of us, evolution was just a chapter in a science book, though we actually studied it in history class. Anyway, most of us just learned enough to pass the test, and moved on. No more life-changing than learning the state capitals.
"Public schools used to teach scripturally-sound moral values, such as a good work ethic, quite frequently."
Since when does being a christian = good work ethic. Some of the worst coworkers I ever had, including a current one, are the same ones who put on a big show about what good christians they are. They're also the same ones who have bullied and berated me for not being religious.
"Associated with teenage atheism are rebellion, free love, drug use and other staples of liberalism. Often, teenage atheists are adopting these principles in rebellion."
I transferred to a Catholic school halfway through my junior year. I saw more teen pregnancy, drug use, alcoholism and cheating than I did all my years in public school combined. Even in public school, it was always the kids from the religious homes who had the best drugs, were always smoking in the bathroom, were the most promiscuous, etc.