Can you become a brain surgeon with GED instead of high school diploma?

No, you cannot become a brain surgeon with a GED instead of a high school diploma. To become a brain surgeon (neurosurgeon), you need a rigorous academic path that starts with a bachelor's degree, followed by medical school (MD or DO), a neurosurgery residency, and potentially fellowships. All of these programs require a high school diploma or equivalent *at minimum*, and most will strongly prefer a college preparatory curriculum. A GED might allow you to *apply* to some undergraduate programs, but a competitive application for medical school, which is incredibly competitive, would require far more than just a GED.