Question 5
Which parent determines the sex of a child, and why?
The right answer is the one marked above.
The father, because his gametes carry either X or Y. Every ovum carries X, so the mother’s contribution is the same whatever the child turns out to be. Which kind of sperm arrives is what makes the difference.
Determining is not choosing. Nobody selects which sperm reaches the ovum first — it is the same chance process as any other fertilisation.