Final answer:
A person with two X chromosomes is typically female. The standard sex chromosome composition for females is XX, and variations like Klinefelter syndrome (XXY) and Turner syndrome (XO) have distinct phenotypic outcomes. In females, the extra X chromosome becomes a Barr body to balance genetic dosage.
Step-by-step explanation:
A person with two X chromosomes is typically female. Sex chromosomes play a crucial role in determining an individual's sex; females usually have two X chromosomes (XX), while males have one X and one Y chromosome (XY). While genetic variations such as Klinefelter syndrome (XXY) or Turner syndrome (XO) result in different sex chromosome compositions, with Klinefelter syndrome typically resulting in a male phenotypic expression and Turner syndrome resulting in a female one, the standard XX combination is associated with females.
Sex chromosomes are a pair of chromosomes involved in sex determination. In humans, two X chromosomes or an X and a Y chromosome define a person's sex. It is also interesting to note that every X chromosome except one undergoes inactivation through the formation of what is known as a Barr body, to ensure a balance in genetic dosage.