The Whole Premise Of This Movie Is Absurd
I have not seen the film, but I have viewed the trailer. This movie appears to revolve around the assumption that Islam and Judaism are ethnicities. They are not. They are both religions and therefore, choices.
Here in the United States, former secretary of state Madeline Albright discovered late in life that her biological parents were Jewish which she found interesting, but it did not stop her from attending church services.
A person's religion is whatever they choose to be. This film would suggest that one has the obligation to choose the religion of one's biological parents, which is ridiculous. The world is full of people who were raised Muslim who later converted to Judaism, and vice-versa, based solely on which faith felt more comfortable to them.
If a man's adoptive parents are Methodists, then later discovers that his biological parents are Episcopalians, I seriously doubt that he would suddenly feel an uncontrolable urge to switch churches (and I also don't think it would make a particularly entertaining movie either).
If this were set in Northern Ireland in the 70s, and was about a Catholic who suddenly discovers he's "supposed to be" a Protestant (or vice-versa), it might make an interesting film, but it wouldn't be a comedy. It would be a serious rumination on the absurdity of how people wind up being who they are, based largely on what the people that raised them tell them they are.
Everyone's faith should be based exclusively on whatever it is they feel most spiritually drawn to. Incidentally, I am an Atheist.