Ключевые слова: anatomy, biology, birth control, cell, cells, cytoplasm, donation, duct, epididymis, fertile, fertilization, flagella, gametes, genetic, gland, gynecology, healthy, histology, human, in vitro, infertile, infertility, magnification, male, medicine, microscope, microscopic, nucleus, organ, penis, reproduction, reproductive, science, scrotum, semen, sex, sperm, sperm cell, sperm donor, spermatids, spermatogonia, spermatozoa, spermatozoid, structure, swimming, tail, test tube, testicles, testis, tissue,