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| At the time of conception, the 23 chromosomes from the egg combine with the 23 chromosomes from the sperm to produce a zygote, or fertilized egg cell, which then has 46 chromosomes. (A) Two of these chromosomes determine sex. (B) The offspring always inherits an X chromosome from the mother. If the father also gives an X chromosome, the offspring will be female or XX. If the father gives an Y chromosome, then the offspring is male or XY. |
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