Though kohanim may waive some of those privileges if they so wish, it is best practice for them not to do so. Their status should be preserved in order to remind us of their special role in the Temple services in Jerusalem. But in a deeper sense, their status should be preserved as a record of their special mission “to guard knowledge with their lips and to teach Torah to those who request it.” Since they are a blessing to the people of Israel, they are commanded in turn to bless the people of Israel: blessed are those who are commanded to bless others. So the status of kohen represents all that is noble and positive in Jewish life and tradition: knowledge, Torah, grace, security and peace.
There exists a body of halachic decisions involving ersatz kohanim. This is because not every person who claims to be a kohen actually is one—and true pedigrees are very difficult to verify today. The halacha adopts a position that entitlement to be regarded as a kohen is a matter of doubt. Great rabbinic decisors, especially in the United States, have often, in cases of dire circumstances, “annulled” the kehuna of an individual.
In the confusion of immigration into the United States at the end of the nineteenth and the beginning of the twentieth centuries, there were people who disguised themselves as kohanim in order to earn the monies of pidyon haben—redemption by the kohen of most first-born males. These people were charlatans, but there were also many others, simple Jews, who had assumed that they were kohanim but possessed no real proof of the matter. Even tombstones inscriptions that one’s father was a kohen were not to be accepted as definitive proof of the matter. This is why DNA results are most interesting and provocative.
The halacha has not yet determined with certainty the trustworthiness of DNA results in matters that require halachic decision. It is thus premature to speculate as to whether DNA testing will ever be used as a method of determining one’s true status as a kohen. Meanwhile, the kohanim should retain the tradition that goes with their presumed pedigree to the best of their abilities.
Shabbat shalom, Rabbi Berel Wein