"Belief in reincarnation is present in all schools of Buddhism, initially stemming from Buddha’s experience of enlightenment. He concluded that three things are necessary for the emergence of a human psyche and the formation of a human embryo; the parents sexual intercourse; ovulation in the mother; the presence of a being in the intermediate state who has the karma to be reborn to those parents at the time. While such beings are influenced by their karma, or actions in their past lives, they also choose the parents to whom they shall be born. So reincarnation is not a matter of predetermination where the future is totally determined by past events."