Composite vs Single Foreign Keys

[Mike Ferris]

Given:

CREATE TABLE `person` (
`ID` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(45)DEFAULT NULL,
`born_in` int(11) DEFAULT NULL,
`lives_in` int(11) DEFAULT NULL,
PRIMARY KEY (`ID`));

CREATE TABLE `country` (
`id` int(11) NOT NULL,
`name` varchar(45) DEFAULT NULL,
PRIMARY KEY (`ID`));

What is the advantage or disadvantage of using a composite FK vs two single FKs? Keeping two single indexes?

ALTER TABLE `person`
ADD INDEX `person_born_in_country_id_idx` (`born_in`),
ADD INDEX `person_lives_in_country_id_idx` (`lives_in`),
ADD CONSTRAINT `person_born_in_country_id` FOREIGN KEY (`born_in`) REFERENCES `country` (`ID`),
ADD CONSTRAINT `person_lives_in_country_id` FOREIGN KEY (`lives_in`) REFERENCES `country` (`ID`);

vs.

ALTER TABLE `person`
ADD INDEX `person_born_in_country_id_idx` (`born_in`),
ADD INDEX `person_lives_in_country_id_idx` (`lives_in`),
ADD CONSTRAINT `person_born_in_lives_in_country_id` FOREIGN KEY (`born_in`,`lives_in`) REFERENCES `country` (`ID`,'ID');