What societal belief does GATTACA challenge regarding genetics?

The correct answer highlights a central theme of GATTACA, which critiques the societal notion that a person's value and potential are solely determined by their genetic makeup. In the film, characters like Vincent demonstrate that despite being genetically inferior according to the society's standards, they possess drive, ambition, and capabilities that allow them to transcend their genetic limitations. This challenges the reductionist view that one's DNA alone defines who they are or what they can achieve.

The film illustrates that environmental factors, personal choices, and determination play significant roles in shaping an individual, promoting the idea that human capabilities are not entirely predetermined by genetics. This perspective counters the prevailing belief in the film's world that validates discrimination based on genetic heritage, ultimately questioning the ethics of a society that values individuals solely based on their predetermined genetic traits.