Editor’s note: This post has been edited from the original to reflect changes in our product. If you want to stir up trouble, start talking about the role genetics plays...

If you have a big head, you may be subjected to a fair bit of teasing, but science may offer you some consolation. People with smaller heads may be at risk for dementia and other cognitive and mental illnesses. Now, scientists have found associations between common genetic variants and measures of head and brain size.