Royalty are no different than any other mortal! The belief that kings are "not as other people" goes back a long way. But it is not true! As Charles 1 found out! As for a "bloodline" if you go back far enough we are all related to each other.
When king George VI was ill, and very near death, one of my officers (I was in the Army at the time) passed the remark that
" This is not just any normal man."
Another officer said,"He's very normal now!"