So I thought. These days, most Orthodox Jews would not consider people converted in a Conservative or Reform branch of Judaism jewish, right? But how do you know, as an Orthodox Jew, that you are 100 % jewish? I mean what if his or hers ancestor back back in a time converted in other branches of Judaism and he or she just do not know it? And you cannot prove it? Or there was no proper conversion whatsoever?
Is there some opinion dealing with this?