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The process by which sperm are formed. Sperm (spermatozoa) are produced by a series of cell division that take place in the seminiferous tubules of a male animals testes. Initially, germ cells divide to produce spermatogonia, which further divide by mitosis to form primary spermatocytes. Each primary spermatocyte then divides by meiosis, a cell division peculiar to the reproductive organs, to form two secondary spermatocytes, each containing half the full number of chromosomes. These finally divide yet again by meiosis to form spermatids, which then mature into spermatazoa.

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