Nope, gender at birth is defined genetically. We all have two complete sets of chromosomes, which are little X-shaped structures that carry our DNA, wrapped around things called histones in the same way thread is wrapped round a bobbin. We get one set of these from the egg cell, and one from the sperm. All the egg cells have normal chromosomes 1-22, and the X sex chromosome. All the sperm have normal chromosomes 1-22 as well, but half of the sperm have an X, and half have a Y. If the embryo gets an X, it’s a girl! If it gets a Y, it’s a boy!
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