[2] After emigrating to the United States in 1889, and, arriving in New York, he studied medicine at the university there.
Fishberg has been associated with Beth Israel Hospital, New York, and is medical examiner of the United Hebrew Charities of that city.
[3] During his time as a medical examiner he recorded skull and nose measurements of Jewish immigrants through which he originally asserted a genetic difference between Jews and non-Jews to describe them as another race along with Joseph Jacobs.
Opposed to the narrow or vertically arranged studies which Maurice Fishberg conducted which completely ignored the Jewish ethnicity ie culture, religion, and even family in the case of adoptions Franz Boas looked at all of those factors as well as across multiple generations and in multiple geographic locations to determine there to be no discernable genetic difference between Jews and non-Jews.
This combined with the growth of what Max J. Kholer called Hitlerism or later Nazism in Germany resulted in a national summit where Franz Boas who had legally and scientifically been determined to be the factually correct opinion on the genetics of the Jewish people presided as guest of honor as Maurice Fishberg along with Ellsworth Huntington discredited their prior works before The Judaens and the Jewish Academy of Sciences on March 4, 1934, to emphatically state that there is no genetic difference between Jew and non-Jew nor and superior race.