The sex of a human child is determined by
- A. the ovum, which may carry either an X or a Y chromosome
- B. the hormones of the mother during pregnancy
- C. the total number of chromosomes in the zygote
- D. the sperm, which carries either an X or a Y chromosome
Explanation
The mother is XX and so every ovum carries an X, while the father is XY and produces X bearing and Y bearing sperm in equal numbers, so it is the sperm that decides. A Y bearing sperm gives an XY male and an X bearing sperm an XX female, which also explains the roughly equal sex ratio at birth. Blaming the mother for the sex of a child has no biological basis whatsoever.
Related questions
Red green colour blindness is far commoner in men than in women because
A woman who is a carrier for colour blindness marries a man with normal colour vision. The probability that any son of theirs is colour blind is
Haemophilia A is caused by the deficiency of
A colour blind girl can be born only if
In X linked recessive inheritance, the criss cross pattern means that a trait typically passes from