Why Teenagers Rebel

Alex Bäcker, Ph.D.

It's well known that teenagers rebel against their parents. As a father who recently survived having all three of his children experience teenagedom at the same time, I can tell you this phenomenon happens almost like clockwork. Conveniently, the English and German languages built the age of adolescence into the very name of the relevant numbers, thirteen through nineteen, giving parents a warning that those years will be…different. 

Then, mysteriously, around age twenty, children rediscover the goodness of their parents.

Some have suggested teenage rebellion is a modern post-WW2 phenomenon. Those are clearly unaware of the words written before 1915 and attributed to Mark Twain:

"When I was a boy of fourteen, my father was so ignorant I could hardly stand to have the old man around. But when I got to be twenty-one, I was astonished at how much the old man had learned in seven years."

How did this rebellious behavior get selected for in evolution?

I posit that teenage rebellion evolved as a mechanism to get teenage boys and girls to leave their tribe and find a mate with different enough genetic make-up, avoiding incest and inbreeding. 

The alpha male(s) in any tribe gets to do most of the mating. Which means that, for a young boy to mate at all, and for a young girl to mate with someone with a different enough genetic make-up to maximize the fitness of her offspring, kids need to leave their tribe.

But leaving your tribe is hard. It's a harsh world out there. Failing an absolute hate for their parents, no kid in their right mind would leave them. So humans evolved to despise their parents when they hit puberty, to force them to leave their tribe and find a mate.

Once a mate is found, after their teenage years, there are advantages of course to rekindling the relationship with their family, so the contempt is only temporary.

So next time your teenage kid gives you a hard time, remember: teenagers are just trying to gather the motivation to build the distance between you and them needed to find themselves a mate and give you grandchildren. Given that birth rates in the US are currently below replacement levels, that should be a goal you can get behind.

The author holds a Ph.D. in biology from the California Institute of Technology. His book, 101 Clues to a Happy Life, written for his three teenage kids, was published May 28th, 2022.