One significant difference between estate law in the United States and the United Kingdom is that in the US we don't have hereditary titles of nobility. The United Kingdom does, and it sometimes leads to disputes over who the rightful heir to the title is.
A current dispute started innocently enough with a family tree project and the Clan Pringle DNA project. DNA evidence revealed that the last holder of the Pringle of Stichell Baronet was not actually descended from the family bloodline. Thus began a fight over the title between two branches of the family.
The Queen has asked the little known Supreme Court, made up of Britain's most senior judges, to decide whether DNA evidence can be used in the case to determine to whom the title rightfully belongs.
The Daily Mail reported this story in "Who's the real aristocrat? Queen demands DNA to be tested in court to settle dispute over 330-year-old baronet title (...but could ruling mean a Utah Mormon is our king?)."Even though we do not have hereditary titles in the United States, if the court allows DNA evidence to be used, then it is possible it could be used to prove whether or not a Utah attorney is actually the true king through descent from George IV.
It could also possibly be used against the Queen in another way. She claims her ancestry back to Henry VII. His claim to a Royal bloodline came through John of Gaunt, the son of Edward III. However, historians have speculated that John was actually the child of an adulterous affair between Edward's wife and another man.
Reference: Daily Mail (October 11, 2015) "Who's the real aristocrat? Queen demands DNA to be tested in court to settle dispute over 330-year-old baronet title (...but could ruling mean a Utah Mormon is our king?)."