Understanding Gametogenesis
Gametogenesis starts with meiosis—a special type of cell division—followed by a maturation period that transforms cells into functional gametes. The male and female processes follow different timelines and cellular behaviors.
Spermatogenesis is the creation of sperm cells in males. This process begins when a diploid germ cell (primary spermatocyte) undergoes meiosis to create four haploid spermatids. These spermatids then mature in the epididymis to become functional sperm cells. Men can produce sperm continuously from puberty until death.
Oogenesis works differently in females. Amazingly, all potential egg cells (oogonia) form when a female is still a fetus! Initially, a female fetus has about seven million oogonia, but most die before birth. The surviving cells enter meiosis I and become primary oocytes, which pause their development until puberty.
💡 Did you know? Female egg cells begin developing before birth but remain paused in development for over a decade until puberty begins!
After puberty, during each menstrual cycle, some primary oocytes resume development. When they divide, they do something unusual—they split their chromosomes evenly but their cytoplasm unequally. Most cytoplasm stays with the secondary oocyte, while the other cell (polar body) gets chromosomes but minimal cytoplasm and eventually dies.