Rodriguez Diaz v. Sierra Martinez

Rodriguez Diaz, then 17, was seriously injured in Puerto Rico when Sierra Martinez's vehicle struck his motorcycle; he alleged he suffered additional harm from mistreatment at two hospitals during treatment. He later moved to New York, turned 18 there (New York's age of majority), and then sued in federal court in Puerto Rico, invoking diversity jurisdiction and alleging he was domiciled in New York even though his parents remained in Puerto Rico (where the age of majority was 21). The district court dismissed for lack of diversity jurisdiction, reasoning that under Puerto Rico's higher age of majority, Rodriguez Diaz was still a minor whose domicile followed his parents'. He appealed.