According to Islamic law can the father of the girl that one wants to marry refuse to give his consent and blessing purely based on the fact that one was not born a Muslim or came from a different ethnic background to them?
It is obligatory on the father of the girl or her paternal grandfather to guard her welfare in accepting the marriage or refusing it. If the guardian in this case sees that the best interest of his daughter is not to marry this person, then he is permitted to refuse.