@Foofie,
Foofie wrote:
... if an individual chose to be Christian after marrying a Christian, would there not be some people that still thought of that individual as Jewish, since his/her mother was Jewish.
I guess you are really referring here to the "ethnic Jew". Perhaps your mother is an ethnic Jew, but not religious. Thus, I would conclude that you too are an enthnic Jew. You could be religious or not in the Jewish religion. But regardless of your religious practices, you are still an ethnic Jew.
But what if you mother is not an ethnic Jew nor is she a Jew-by-choice, but, you would like to become a religious Jew. If you undertake religious studies with a Rabbi for about 6 months, you may undergo a conversion ceremony and become Jewish.
If that is your desire, you would be a Jew-by-Choice, whose ethnicity may or may not be considered to be Jewish depending upon the criteria employed for this determination.
In addition to the above, we also have a group of Jews, who call themselves
"Jews for Jesus". I think this group consists of ethnic Jews, who are now Christian by faith.