JAMB Biology 2014 Paper

Concept:In humans, the sex of a child is determined by the father’s sperm: an X sperm gives a female $\mathrm{XX}$, while a Y sperm gives a male $\mathrm{XY}$.Explanation:A female child receives one X chromosome from her mother and one X chromosome from her father.All 10 children are female, meaning all fertilizing sperm carried the father’s X chromosome.Therefore, the sex outcome was determined by the man’s X chromosome, not his Y chromosome.Answer:A. The sex determination was by the man's X chromosome