Sex Determination

• Human Chromosomes

  • Ordinary human body cells contain 23 pairs of chromosomes
  • 22 pairs control characteristics only, but one of the pairs carries the genes that determine sex
  • In females, the sex chromosomes are the same (XX)
  • In males, the sex chromosomes are different (XY)

  
• Determining Sex

  • The inheritance of sex can be shown using a genetic diagram (known as a Punnett square), with the X and Y chromosomes taking the place of the alleles usually written in the boxes