Germ cells are the cells responsible for reproduction and passing genetic information from one generation to the next. Synonyms for germ cells include reproductive cells, gametes, sex cells, ova, and spermatozoa. These cells undergo meiosis, a specialized division process, to ensure genetic variation in offspring. Germ cells are essential for sexual reproduction in animals and humans. In female animals, germ cells develop into eggs, whereas in males, they develop into sperm. Germ cells are unique cells in that they carry half the genetic information and require sex hormones to properly develop. Understanding germ cell biology is critical for advancing fertility treatments and developing new therapies for infertility and other reproductive disorders.