What physical change did Vincent make to match Jerome?

Vincent made a significant physical change by cutting and dyeing his hair to match Jerome’s appearance. This alteration was part of his efforts to align himself with Jerome, who was a genetically superior individual—essentially making it easier for Vincent to navigate the society that values genetic perfection. Changing his hair not only represents a physical adaptation but also symbolizes his deep desire to fit into the role assigned to someone like Jerome, reflecting the themes of identity and societal expectations present in "GATTACA."

While options like increasing height or changing eye color are also noteworthy physical attributes, the specific act of hair transformation is more directly depicted in the film and is emblematic of the lengths to which Vincent goes to conceal his true identity. Dyeing hair is practical and achievable for him, demonstrating a relatable human effort to conform to societal standards.