In some quarters, the opinion is that spaying too soon may produce cancer in females, and possibly have negative impact on bone development. I've also read/heard concerns about weight gain being more likely once spayed. Not sure if one can do anything about the latter (if it's a true concern: some call it a myth), but how many months/cycles should one wait before spaying? That is, assuming there is really a concern about spaying before the first cycle. Is there?