At how many weeks can the sex of the fetus be visually recognizable?

The sex of the fetus becomes visually recognizable at approximately 12 weeks of gestation due to the development of external genitalia. At this stage, an ultrasound may show the early structures that differentiate the male and female genitalia, although the accuracy of determining sex at this early point in pregnancy can be variable.

By this time, the external genitalia starts to take on distinguishing characteristics, allowing trained technicians to make a more informed judgment about the fetus's sex during an ultrasound examination. As gestation progresses, especially around 16 weeks, the distinction often becomes clearer and more reliable, but the initial recognizable features typically emerge around the 12-week mark, making this the most appropriate timeline to reference for the question.