12 Surprising Scientific Facts About Girls

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9They're Born Afraid of Bugs

Girls are four times more likely than boys to fear spiders in all of their creepy crawly glory. Researchers found that girls are genetically predisposed to develop fear for potentially dangerous insects. Baby girls start to associate pictures of spiders with fear at only 11 months old while boys remain indifferent. Fascinating.

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10They See a Whole Lotta Red!

Girls see more variations of the red-orange spectrum, thanks to a gene that sits on the X chromosome. Researchers found girls have two copies of the chromosome and boys have only one ... giving us the real ability to see red.

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12Their Hearts Beat Fast

When it comes to resting heart rates, girls are ahead of boys ... from the womb (wives' tale) to adulthood (science). Men have larger hearts and lungs than women. They're able to oxygenate more blood as their hearts pump more per minute. To get a similar oxygen saturation, women's hearts have to pump faster.

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