Before DNA testing, there was no way to prove paternity, so it was understandable that Judaism would be passed on through the maternal line. So why doesn’t the transmission of status—whether you are one of the three “castes” of Judaism: Kohen, Levi or Yisrael—require the same certainty as the transmission of religion? A kohen (one descended from the priestly class with special duties in the Temple more than 2000 years ago) is always given the honor of the first aliyah during a Torah reading and gives the “priestly blessing” at a synagogue service.