By Jonah Comstock, published on September 3, 2012 - last reviewed on February 5, 2013
Here's a seemingly silly question: Is 571 a he or a she? Deep down, you probably think of it as masculine. When people look at gender-ambiguous prompts like babies' faces, they're more likely to think of them as male when they're paired with an odd number, reports a study led by James Wilkie of Northwestern University. The finding suggests that our beliefs about gender may creep into everything from phone numbers to pricing—but why?