Some sociology in the comments
It's good to bear in mind that there are important ways in which heredity influences environment: Kids who are physically attractive and above average at motor coordination are more liked by their peers. Physically attractive kids are perceived by teachers as smarter, and are favored. Kids who really are quite smart, even if not physically attractive, are seen as smart by teachers. Simple things like this have a big influence on how many smiling faces kids see in their early years, and that number's a powerful feature of social environment.
God I hate these people so fucking much