I understand that an adopted child can go through conversion, that's not my question.
My question is why does a newborn of a Jewish convert count but not an adopted? Why must the adopted child go through conversion but not the newborn?
Every definition of Ethnicity I've seen says that it's a subdivision of the concept of "race".
Difference Between Ethnicity and Race | Difference Between | Ethnicity vs Race
This basically implies that Ethnicity is an "Enhanced" definition of race into sub-groups. I'd like to see a single source that says Japanese and Germans can be of the same Ethnicity.
I've seen government forms that ask for "Ethnicity" and ask if you're black or asian or whatever, so apparently not even the government is clued in on this alleged difference.
By all means otherwise show a single definition of ethnicity that discludes "Race" as the foundation.
Then I would suggest more reading on the subject.
The US is atypical in that we associate race and ethnicity in offical forms.
Ethnic group - Wikipedia, the free encyclopediaIn the United States of America, the term "ethnic" carries a different meaning from how it is commonly used in some other countries due to the historical and ongoing significance of racial distinctions that categorize together what might otherwise have been viewed as ethnic groups.
As for definitions, here ya go:
United Nations Statistics Division - Demographic and Social StatisticsSome of the criteria by which ethnic groups are identified are ethnic nationality (i.e., country or area of origin, as distinct from citizenship or country of legal nationality), race, colour, language, religion, customs of dress or eating, tribe or various combinations of these characteristics. In addition, some of the terms used, such as race, origin or tribe, have a number of different connotations.
Ethnic group - Wikipedia, the free encyclopediaAn ethnic group is a group of people whose members are identified through a common trait. This can, but does not have to, include an idea of common heritage, a common culture, a shared language or dialect.[1] The group's ethos or ideology may also stress common ancestry and religion, as opposed to an ethnic minority group which refers to race.[2][3][4][5] The process that results in the emergence of an ethnicity is called ethnogenesis. Some ethnic groups are marked by little more than a common name.
Race and Ethnicity in Rural America | Rural Communities ExplorerAn ethnic group is a "socially defined group based on cultural criteria, such as language, customs, and shared history"
Ethnic group | Define Ethnic group at Dictionary.com   [eth-nik] Show IPA
adjective 1. pertaining to or characteristic of a people, especially a group (ethnic group) sharing a common and distinctive culture, religion, language, or the like.
2. referring to the origin, classification, characteristics, etc., of such groups.
3. being a member of an ethnic group, especially of a group that is a minority within a larger society: ethnic Chinese in San Francisco.
4. of, pertaining to, or characteristic of members of such a group.
5. belonging to or deriving from the cultural, racial, religious, or linguistic traditions of a people or country: ethnic dances.
Ethnicity vs Race - Difference and Comparison | DiffenThe traditional definition of race and ethnicity is related to biological and sociological factors respectively. Race refers to a person's physical appearance, such as skin color, eye color, hair color, bone/jaw structure etc. Ethnicity, on the other hand, relates to cultural factors such as nationality, culture, ancestry, language and beliefs.
Sociology: Race and Ethnicity DefinedEthnicity refers to shared cultural practices, perspectives, and distinctions that set apart one group of people from another. That is, ethnicity is a shared cultural heritage. The most common characteristics distinguishing various ethnic groups are ancestry, a sense of history, language, religion, and forms of dress. Ethnic differences are not inherited; they are learned.
And some more scholarly examples:
Ethnic Identity - Joseph E. Trimble, Ph.D.
http://isites.harvard.edu/fs/docs/i...ntroduction Ethnic Groups and Boundaries .pdf
http://gbl.indiana.edu/baumann/Baumann 2004 - Defining Ethnicity.pdf
As for you question about the child: Because one is born of a Jewish mother, and one is not. And, as we have already repeatedly established, Judaism accepts two avenues into the group: maternal descent and conversion.