Genetics

In 1930, four identical baby girls were born to a family in a small Midwestern town. Genetically, they were as similar as four humans can be-monozygotic quadruplets, sharing 100% of their DNA. They grew up in the same house, with the same parents, eating the same food, attending the same schools. And all four developed schizophrenia. On the surface, this seems like a clear-cut case of genetic determinism: identical genes, identical illness. ...

When I was in college, a professor made a claim that stopped me mid-note: “Intelligence is about 50-80% heritable. Your genes, not your effort or education, largely determine how smart you’ll be.” I was stunned. And honestly, a little angry. I’d grown up believing that hard work mattered most. That anyone could achieve anything with enough effort. That your background didn’t determine your destiny. Was all of that naive? Were we just puppets dancing to our genetic programming? ...