Ajout de deux foreign key

[/contents/1058-sql-modification-de-table alter table] enfant add constraint fk_enfant_parent_id_parent1_id_parent2 foreign key (id_parent1, id_parent2) references parents(id_parent1,id_parent2) on delete cascade on update restrict;
ERROR 1005 (HY000): Can't create table `bellefamille`.`#sql-2ee0_2` (errno: 150 "Foreign key constraint is incorrectly formed")

enfant | CREATE TABLE `enfant` (
  `id_enfant` int(11) NOT NULL AUTO_INCREMENT,
  `nom` varchar(100) NOT NULL,
  `prenoms` varchar(255) DEFAULT NULL,
  `date_nais` date DEFAULT NULL,
  `id_parent1` int(11) DEFAULT NULL,
  `id_parent2` int(11) DEFAULT NULL,
  PRIMARY KEY (`id_enfant`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=latin1

 enfant_local | CREATE TABLE `enfant_local` (
  `id_enfant` int(11) NOT NULL AUTO_INCREMENT,
  `id_local` int(11) NOT NULL,
  PRIMARY KEY (`id_enfant`,`id_local`),
  KEY `enfant_local_ibfk_1` (`id_enfant`),
  KEY `enfant_local_ibfk_2` (`id_local`),
  CONSTRAINT `enfant_local_ibfk_1` FOREIGN KEY (`id_enfant`) REFERENCES `enfant` (`id_enfant`) ON DELETE CASCADE,
  CONSTRAINT `enfant_local_ibfk_2` FOREIGN KEY (`id_local`) REFERENCES `local` (`id_local`) ON DELETE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=latin1 |