Is it true that sperm determine the sex of a baby pregnancy?
Yes, it is the sperm that determines the sex of a child. A woman’s ovum and a man’s sperm each carry a single set of 23 chromosomes. A unique mix of genes is spread over these 23 chromosomes, and when an egg is fertilized the embryo has 23 pairs of chromosomes, one set from each parent. Numbers 45 and 46 (pair 23) are the sex chromosomes, which determine the sex of the child. The mother’s egg always carries the female chromosome (which is given the label X). The father’s sperm, however, carries either the female chromosome, X, or the male one (labelled as Y). When an egg is fertilized, the resulting embryo either has an XX or an XY as its 23rd pair – the former develops into a girl, the latter into a boy.