chromosomes

• each cell in the body contains 46 chromosomes (23 pairs)
• female chromosome - XX
• male chromosome - XY
• if the sperm carries an X chromosome the embryo will be female
• if the sperm carries a Y chromosome, the embryo will be male
• Chromosomes are determined at conception
• originally, both male and female foetuses have genitalia that appear female
• at 6 weeks after conception, gods begin to develop differently

  • females develop ovaries
  • males develop testes
• in male foetuses, the testes will release testosterone causing the male genitalia to develop