Just since 2007, Iowa’s teen birth rate has fallen nearly 40 percent.
The national teen birth rate fell 9 percent in 2014, to 24.2 births per 1,000 women ages 15 through 19, according to the federal Centers for Disease Control and Prevention.
The national rate has dropped 42 percent since 2007.
RELATED: Abortion numbers plummet in Iowa“It’s amazing how fast these rates are changing,” said Gretchen Livingston, a demographer for the Pew Research Foundation.
However, one of the most disturbing characteristics of Generation Z, or "i Gen" in Twenge's parlance, is a suicide rate that has surpassed the homicide rate in that age group.
Twenge thinks smartphone use may play a crucial role in contributing to that.
— Teenagers in Florida are in trouble after having sex in a high school bathroom and then posting a recording of it on social media.