Final answer:
Castration anxiety occurs during Freud's phallic stage of development, where children become aware of their bodies, recognize gender differences, and experience conflicts related to their desires for their opposite-sex parent.
Step-by-step explanation:
According to Freud's psychosexual stages of development, castration anxiety occurs during the phallic stage. In this stage, which occurs from ages 3 to 6, children become aware of their bodies and recognize the differences between boys and girls. They experience conflict when they feel desire for the opposite-sex parent and jealousy and hatred toward the same-sex parent. For boys, this conflict leads to castration anxiety, which is the fear of punishment from their father for their feelings.