Is there any evidence to suggest that if one or both of the parents went to grammar school, that their progeny will have a better chance in the eleven plus?
We know that the landed gentry will pass their lands and possessions onto their children. After all, a King and Queen are allowed to pass the throne onto their eldest child. The succession in our royal family, for example, is secured. (The senior members of the present royal family have not needed to worry about grammar school!)
There is possibly an economic bond that binds families and generations together. Perhaps some children are likely to follow the occupations of their parents. Good luck to all concerned!