To make a baby you need a sperm cell and an egg cell. The sperm cell comes from the daddy and the egg cell comes from the mommy. When the sperm and egg meet, they make a tiny baby that is smaller than a grain of salt. The baby grows in the mommy's tummy for nine months. Then the baby is ready to come out.
When a man and a woman have sexual intercourse, millions of sperm are released into the woman. The sperm meet the egg cells from the woman and fertilizes it to make a zygote, a tiny little baby no bigger than your fingertip. Through the course of nine months, the baby grows and then is delivered by the mother. Or, if the case needs it, they can be delivered through c-section (Cesarean Section) which is when the stomach is cut open in surgery and the baby is surgically removed.