Haemophilia B has been known to arise spontaneously in the children of older fathers, and the Duke of Kent was fifty-one when Victoria was born. Nicholas Wright Gillham proposes that the haemophilia mutation could have first occurred with either Victoria or the Duke of Kent. Gillian Gill and her son Christopher, an infectious disease specialist, also view a genetic mutation as the most likely possibility; Gillian Gill writes that "a few historians in recent years have found it seductive" to doubt Victoria's stated paternity because a random mutation is "an unexciting solution". Helen Rappaport concurs, remarking that "the best and most logical" explanation is that haemophilia first appeared in Victoria as a mutation.