Question 43
Chromosomes, DNA and Sex LinkageA couple has 10 children, all female. Which of the following best explains the situation?
- A.The sex determination was by the man's X chromosome.
- B.The man's sperm count is low.
- C.The woman is not capable of producing male children.
- D.The sex determination was by the man's Y chromosome.
Show the answer and explanation
Answer: A (The sex determination was by the man's X chromosome.)
Explanation
The mother always gives an X; a child is female when the father's sperm also carries an X. So each daughter came from a sperm with the man's X chromosome.