How can one deal with parents who discriminate in their treatment of children based on gender, preferring males over females, and causing psychological and material harm to their only daughter?

Fathers must be just among their children in treatment and gifts, because favoritism inherits resentment. A daughter's service to her parents stems from her obligatory obedience and dutifulness, and this right is not forfeited by their favoritism of males or their harshness. She should feel that she is fulfilling the command of Allah and His Messenger in this regard. We advise parents to be just among their children, and we recall the Prophet's (peace be upon him) saying: "Fear Allah and be just among your children."