The Female and Male Reproductive System [for teens]
The human reproductive system is an organ system by which humans reproduce by giving birth to living offspring. In human reproduction, two types of sex cells, or gametes, are involved. The male gamete or sperm and the female gamete, the ovum. When sperm fertilizes an egg, this fertilized egg is called a zygote. After a long process it becomes an embryo and later a fetus.