Is it permissible for a mother to waive her share of land to her male children, so that the male’s share is double that of the female, while the father’s inheritance remains as it was after his death?

The most sound opinion regarding justice between children in gift-giving is equality between the male and the female, based on the hadith: "Be equitable among your children in gift-giving. If I were to prefer anyone, I would have preferred women." Some scholars, however, are of the view that the male should be given double the share of the female. Therefore, the mother must keep the matter as it is; because her giving her share to the sons is considered an injustice to the daughters.