You know, a quick DNA test would put such controversies to bed.  As a matter of fact, I would suggest making DNA analysis a prerequisite for scholarships and other social benefits reserved for ethnic groups which have experienced historical discrimination.  If you are ethnically Jewish, a DNA test will confirm it.  The same if you are aboriginal.  Why would you ever take someone at their word on the issue of identity when there's money/status on the line?

It is not the case that identity is mutable and we can all choose our own.  This is where the left assaults the truth just as brutally as the right does.  Despite what the dogmatic would have you believe, there are actually facts in this world, both historical and biological.  People are deluding themselves if they think they can escape the facts by adopting a label.