Why didnt the two sons of Queen Victoria Alfred and Arthur display hemophilia?

Queen Victoria had four sons

Albert Edward

Arthur

Alfred

Leopold

The reason why Albert Edward, Arthur and Alfred did not display hemophilia is because they did not have it. Hemophilia is a sex linked gene. Leopold got hemophilia because Victoria carried the gene. She had one healthy X chromosome and an X that had the gene for hemophilia. Leopold got the X with hemophilia and the other boys got the healthy X chromosome