Below is an article written by Rabbi Yaakov Kleiman attesting to the genetic uniqueness of Jews worldwide. Most non-Jews have always just thought of Jews as “a people with a different religion.” However, Jews have always viewed themselves as a race, and genetic testing supports this. There are even Jewish-specific genetic diseases (Tay Sachs disease) that are exclusively a Jewish phenomenon, giving more evidence to long periods of breeding isolation. Could you ever imagine a Catholic priest boasting about the genetic identity of Catholics? No, because it doesn’t exist. Christianity has never specifically focused on race, unlike Judaism.
If you study Jewish texts like the Talmud, much of it is a blueprint on how to maintain the racial integrity of the Jewish people while here on earth, and it gives very little importance to reaching an afterlife. Up until recently, it has almost been strictly forbidden for Jews to marry non-Jews. Today, many Jewish sects still prohibit intermarriage and there are even large movements within some parts of the Jewish community to keep this tradition alive. Furthermore, many converts coming into Judaism are seldom accepted by Jews as being truly Jewish. Jews have always used someone’s lineage to determine if they are Jewish, and give little importance to the person’s current faith. In fact, a large proportion of Jews are actually atheist but still consider themselves Jewish, and definitely still act with Jewish interests in mind.