Birth-Given-Right

"Birth-Given-Right" is deeply rooted in Christian and Jewish religions, but not in Islam. It is related to the rights of the First-Born child. For example: A) The story of Abraham, Sarah, Ishmael and Isaac, where the right were given to Isaac instead of Ishmael, based on the fact that Isaac, though he was not the first-born child, he had the blood of his father and his mother, Sarah, who was Abraham's first wife, and B) The story of Isaac, Rachel, Esau and Jacob, where the rights were given through trickery to Jacob though he was not the first born. You should know that both sons in this case had the blood of the father and the mother. Apologists defend the trickery by mentioning that the Biblical part where Esau sold his rights to his brother, Jacob, for some food.

1. Is the "Birth-Given-Right" the right thing to do?, 2. Should it be given to the son who is worthy?, and 3. The "Birth-Given-Right" has had it repercussions on the human history; what are these repercussions?