Just as in coin-flipping you can get two heads in a row, but it doesn't mean you won't get tails on the next flip. Some people may believe that VHL only occurs in one gender , based on their own family experience. But this is a random occurrence. VHL occurs equally in males and females. Some people believe that VHL only happens at later stages of life .
Children can have issues from very young ages.
Conversely, if someone has reached a certain age , and haven't had symptoms, then they sometimes believe they must be in the clear. Not necessarily so. There are people who have been diagnosed for the first time in their 70's or 80's. Some families believe that they will have only one of the VHL issues , but they may not have seen it yet in their relatives, but we don't yet have enough information to say with any certainty that there will be only certain aspects of VHL in a family, which is why we recommend screening for all. But those other traits have nothing to do with the gene for VHL, so we can't rely on those as a way of guessing who may or may not be affected.