Everybody hopes their toddlers will "play nice," and it can be shocking when they suddenly turn into biting, hitting, kicking little beasts. A new study gathered data from more than 1200 children ages 1 to 4, and found that, to a large extent, their tendency toward physical aggression is genetically programmed and not caused by environmental factors such as watching violent cartoons on television or witnessing domestic strife. "Parents often feel guilty," lead author, Eric Lacourse, a professor at the University of Montreal, tells Yahoo Shine. "They should look at physical aggression as a normal phase of development."
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The study compared over 660 sets of non-identical and identical twins. It found that the pairs who shared 100% of their DNA were far more likely to exhibit the exact patterns of aggression than fraternal twins who grew up in the same environment. In a statement, the researchers said that their results challenge previousRead More »from Toddlers: Why the Bad Seed Theory Isn't Far from the Truth