8 Scientific Reasons Why Teenagers Are Completely Insane

5. They Grow Up So Fast€ No, Really

Sometimes it seems as though kids grow up so fast these days. There are 14-year-olds wandering around that look like they might have put a deposit down on their first house and that only reliable way to sort the kids from the adults is to shout that Urban Outfitters has a sale on and see who runs. This is partly due to the fact that you're getting out of touch, granddad, but it is true that teenagers, girls in particular, are maturing earlier and earlier. In the past 150 years, the age at menarche (that's when a girl's periods start) has positively plummeted from an average age of 17 to just 12-years-old, and the number of girls getting their periods (i.e. reaching sexual maturity) before the age of 11 is on the rise. The boys are going through something similar, but with limited research and less reliable indicators, it's trickier to figure out the trend just yet. No one really knows why kids are hitting puberty earlier and earlier. Back in 1991, some research suggested that girls with more disrupted home lives, particularly ones with an absentee father, are more likely to experience accelerated puberty. Stress in general has also been found to bring puberty forward as high levels of cortisol interfere with the sex hormones. No one has managed to come up with a hard and fast answer as to why our kids are growing up so fast, but with a five year difference in the age of menarche, we can be sure that they definitely are.