Is the gift presented by a father to his male children only permissible, it being an empty plot of land given equally to them for building houses upon, while there are seven married sisters? And if it is not permissible, then what should our father give to the daughters?

The most authoritative opinion is the obligation of justice among children in gifts and endowments, so that the male is given the same as the female. If a father gifts a piece of land to his male children, he must gift the females similarly, or reclaim what he gifted to the males. Ibn Qudamah said: "If he singles out some of them with his gift, or differentiates between them in it, he has sinned, and equality becomes obligatory upon him through one of two matters: either returning what he favored some with, or completing the share of the other."