Something eugenic relates to the idea that self-selecting genetic characteristics, like hair or eye color, can improve a race. The Nazis' eugenic plans to create a "master race" marked one of the darkest periods in the twentieth century.
The adjective eugenic traces its roots from the Greek word eugenes, meaning "well-born." The field of eugenics aimed in the nineteenth and twentieth centuries to improve the characteristics of a race by promoting certain qualities in its offspring, which they then would pass on to future generations. But it also tried to prevent people with "unfavorable" qualities from procreating. This philosophy has greatly fallen out of favor since World War II, especially among biologists.