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In humans, the sex of a child is determined at fertilisation by
Awhether the ovum carries X or Y
Ban autosomal gene on chromosome 7
Cthe mother's age
Dwhether the sperm carries X or Y
Answer & Solution
Correct answer: D. whether the sperm carries X or Y
Females are XX, so every egg carries an X. Males are XY and produce two kinds of sperm — X-bearing and Y-bearing — in roughly equal numbers. The sperm that wins fertilisation decides whether the offspring is XX (girl) or XY (boy).
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