Final answer:
In humans, the sex of the offspring is determined by the sex chromosome carried by the sperm cell.
Step-by-step explanation:
In humans, the sex of the offspring is ordinarily determined by the sex chromosome carried by the sperm cell. The egg cell always contributes an X chromosome, while the sperm cell can contribute either an X or a Y chromosome. If the sperm carries an X chromosome, the resulting zygote will have two X chromosomes and develop into a female. If the sperm carries a Y chromosome, the resulting zygote will have one X and one Y chromosome and develop into a male.
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