Genetics has proved that there has been practically no conversion among MEN, at least not for thousands of years, and then only from similar population groups (Edomites, Caananites etc.). That why different Jewish populations have such similar y-chromosome markers. There has been substantial conversion among women, although even this too ceased about 1000-1500 years ago. It's actually quite remarkable but true: genetically, Jews are still one population group -- even though some look European, and other look quite Arab.
Jews who converted out assimilated. It's one of the reasons that certain European populations show some "Jewish" genetic markers. For instance, a study that just came out shows that 20% of Spain has distinctively Jewish markers, indicating partial ancestry from Sephardic Jews.
http://www.iht.com/articles/2008/12/04/europe/gene.php
This would lend issue to many groups wether Ethiopian the Black Jews of your area Chicago could claim they are Jewish and if they could through DNA how many millions could return there?
Anyone who converts is eligible under the law of return. The Ethiopian Jews converted 2000 years ago, and have been Jews since. Genetically they don't resemble other Jews, but as a matter of Jewish law they are just as Jewish as me. And eligible under the law of Return. The "black Jews" in Chicago (who are really Christians) have not converted. And they are not eligible under the law of Return, although some have moved to Israel in other ways.
There is much written on why the study was bad, I would like to see something on why it was correct.
But how would you account for the Jews who knew there tribes in Ancient Israel that brought fourth the Christian faith? basically all the first followers of Jesus were Jews? not one gentile, they all had families all jews as well? did they just fizzle out as fas as there DNA is concerned? Why would they have less Hebrew DNA then of a Modern Jewish person who does not know there tribe or has been assimilated?
Or say a Jew who converts to another religion? how does that change there DNA? this is what I don’t understand what you are saying in regards to genetics?
You are either a Jew or a Gentile..What does it matter if you convert to Islam Christianity, Scientology etc...