If some property is endowed to a child that is still in the womb of its mother, the validity of it is problematic (maḥall al‑ishkāl),[4] and it is necessary to observe precaution (iḥtiyāṭ) here. However, if some property is endowed for persons who are currently alive, and after them for those who will be born in the future, then the endowment is valid even if the latter are not in the wombs of their mothers at the time of making the endowment.
For example, it is valid if a person endows something to his children, and after them to his grandchildren, and to each generation to use the endowment after the previous generation.