Given a scientific passage and an answer, generate a question for the given answer.
Q: Passage: A sex chromosome is a chromosome that determines the sex of an organism. Humans have two sex chromosomes, X and Y . Females have two X chromosomes ( XX ), and males have one X and one Y chromosome ( XY ). An autosome is any chromosome other than a sex chromosome. If a trait is autosomal it will affect males and females equally. Answer: sex chromosome
A:
What chromosome determines the sex of an organism?