It was widely reported that Diana, Princess of Wales (not
"Princess Diana" - that was never her title
) adamantly refused to have the boys circumcised, although Princes Philip, Charles, Andrew and Edward all were.
A couple of years after Diana's death, Prince William was admitted to hospital for what was described as a "routine hernia operation". There were suggestions that this was media-speak for a circumcision but it has never been proven either way. It is unusual that a lad in his late teens would need "a routine hernia operation" - but not unknown, given that the princes play a lot of contact sport and ride, for polo. So, I think that the general opinion is that there was nothing suspicious about the hospital visit and that the boys remain as Diana wished.