The male reproductive system produces and delivers sperm to the female reproductive system. Its main organs include the testes, which produce sperm and testosterone; the epididymis, where sperm mature and are stored; the vas deferens, a tube that carries sperm; the seminal vesicles and prostate gland, which produce seminal fluid that nourishes and transports sperm; and the penis, which delivers sperm into the female reproductive tract. The female reproductive system produces eggs, receives sperm, provides a site for fertilization, and supports the development of a fetus. Its main organs include the ovaries, which produce eggs and hormones like estrogen and progesterone; the fallopian tubes, which transport eggs from the ovaries to the uterus and are the usual site of fertilization; the uterus, a muscular organ where a fertilized egg implants and develops; the cervix, the lower, narrow part of the uterus that opens into the vagina; and the vagina, a muscular tube that connects the uterus to the outside of the body and receives sperm during intercourse.