Different US states have rules about names. Some require only English characters. They may say that surname must have at least 2 letters. Many exclude numbers and special characters. There are maximum name lengths.It is, however, the state registrar who might have the authority to reject a name, not hospital staff unless the restriction was in the law. Birth certificates now days are submitted electronically by hospital EMR systems to state vital records systems, and those systems impose the rules on character sets and name lengths.Several countries with rather severe restrictions on the appropriateness of names. There are boys named u201cSueu201d in the US, but some other countries wouldnu2019t allow it.