In Ashkenazi populations, which make up around a third of Jews in total, careful genetic counseling has effectively eradicated Tay-Sachs. I suppose you could call this a form of soft eugenics in its purest nonjudgmental sense. It was called a Jewish disease at first and that stuck, carried along by prejudice and ignorance. Now, because of an understanding of genetics and inheritance, it most certainly is not a Jewish disease at all.
