Fetus
          Born
                    Infancy
                ­                Babyhood
                                             Early Childhood
                                                       ­  Middle Childhood
                                                       ­                        Puberty
                                                         ­                            Adolescence
                                                                ­                                   Maturity
                                                        ­                                                    Old
         ­                                                                 ­                                        Die