"Born Sexy Yesterday" is a trope that describes a character, typically a woman, who is physically attractive yet portrayed as childlike or naive, often with a level of intelligence or maturity that contradicts her appearance or behavior. These characters typically lack real-world experience, creating a dynamic where their sexual appeal contrasts with their innocence and unfamiliarity with social norms. This trope is prevalent in science fiction and gained critical attention after a 2017 video essay by YouTuber Jonathan McIntosh, known as Pop Culture Detective.