Who is a Jew? in the context of "Jewish religious movements"

Messianic Judaism is a syncretic Protestant Christian religious sect that incorporates elements of Jewish practice. It considers itself to be a form of Judaism but is generally considered to be a form of Christianity, including by all mainstream Jewish religious movements. Its roots are in Christian missionary activity aimed at Jews in the 19th and 20th centuries, particularly in North America.

Messianic Jews believe that Jesus was the Messiah and a divine being in the form of God the Son (a member of the Trinity), some of the most defining distinctions between Christianity and Judaism. Messianic Judaism is also generally considered a Protestant Christian sect by scholars and other Christian groups.

Conversion to Judaism (Hebrew: גִּיּוּר, romanized: giyur or Hebrew: גֵּרוּת, romanized: gerut) is the process by which non-Jews adopt the Jewish religion and become members of the Jewish ethnoreligious community. It thus resembles both conversion to other religions and naturalization. The procedure and requirements for conversion depend on the sponsoring denomination. Furthermore, a conversion done in accordance with one Jewish denomination is not a guarantee of recognition by another denomination. Normally, though not always, the conversions performed by more stringent denominations are recognized by less stringent ones, but not the other way around. A formal conversion is also sometimes undertaken by individuals who are raised Jewish or have Jewish ancestry but who may not be considered Jewish according to stringent interpretations of traditional Jewish law.

There are some groups that have adopted Jewish customs and practices. For example, in Russia the Subbotniks have adopted most aspects of Judaism without formal conversion to Judaism. However, if Subbotniks, or anyone without a formal conversion, wish to marry into a traditional Jewish community or immigrate to Israel under the Law of Return, they must have a formal conversion.

Israel has two primary pieces of legislation governing the requirements for citizenship, the 1950 Law of Return and 1952 Citizenship Law.

Every Jew has the unrestricted right to immigrate to Israel and become an Israeli citizen. Individuals born within the country receive citizenship at birth if at least one parent is a citizen. Non-Jewish foreigners may naturalize after living there for at least three years while holding permanent residency and demonstrating proficiency in the Hebrew language. Naturalizing non-Jews are additionally required to renounce their previous nationalities, while Jewish immigrants are not subject to this requirement.

Jewish identity is the objective or subjective sense of perceiving oneself as a Jew and as relating to being Jewish. It encompasses elements of nationhood, ethnicity, religion, and culture. Broadly defined, Jewish identity does not rely on whether one is recognized as Jewish by others or by external religious, legal, or sociological standards. Jewish identity does not need to imply religious orthodoxy. Accordingly, Jewish identity can be ethnic or cultural in nature. Jewish identity can involve ties to the Jewish community.

Conservative and Orthodox Judaism base Jewishness on matrilineal descent. According to Jewish law (halakha), all those born of a Jewish mother are considered Jewish, regardless of personal beliefs or level of observance of Jewish law. Progressive Judaism and Haymanot Judaism in general base Jewishness on having at least one Jewish parent, while Karaite Judaism bases Jewishness only on paternal lineage. While these differences between the major Jewish streams are a source of the disagreement and debate about who is a Jew, all interpretations of Rabbinic Judaism agree that a valid Jewish identity may also be achieved via conversion.

Jewish religious movements, sometimes called "denominations", include diverse groups within Judaism which have developed among Jews from ancient times, including Qaraite Judaism and the majority group, Rabbinic Judaism. Samaritans are also considered ethnic Jews by the Chief Rabbinate of Israel. However, experts frequently classify them as a sister ethnicity practicing a separate branch of Yahwism. Today in the West, the most prominent divisions are between traditionalist Orthodox movements (including Modern Orthodox Judaism and the ultratraditionalist Haredi Judaism) and modernist movements such as Reform Judaism originating in late 18th century Europe, Conservative Judaism originating in 19th century Europe, and other smaller ones, including Reconstructionist Judaism and Jewish Renewal movements, which emerged later in the 20th century in the United States.

In Israel, variation is moderately similar, differing from the West in having roots in the Old Yishuv and pre-to-early-state Yemenite infusion, among other influences.

Several groups of people have claimed lineal descent from the Israelites (or Hebrews), an ancient Semitic-speaking people who inhabited Canaan during the Iron Age. The phenomenon has become especially prevalent since the founding of the State of Israel in 1948. The country's Law of Return, which defines Jewishness for the purpose of aliyah, prompted many individuals to claim Israelite ancestry with the expectation that it would make them eligible for Israeli citizenship. The abundance of these claims has led to the rise of the question of "who is a Jew?" in order to determine the legitimacy of one's Jewish identity. Some of these claims have been recognized, while other claims are still under review, and others have been outright rejected.

There were numerous events in Jewish history that forced the Jewish people into exile from the Land of Israel, compelling them to disperse throughout many of the world's regions. The most significant of these events are recorded in the Hebrew Bible, but have been attested by extra-biblical evidence as well. The most notorious exilic occurrences were: the fall of the Kingdom of Israel to the Neo-Assyrian Empire in c. 720 BCE; the fall of the Kingdom of Judah to the Neo-Babylonian Empire in c. 586 BCE; the Roman siege of Jerusalem in 70 CE; and the Bar Kokhba revolt in the 130s CE. A number of these communities of the Jewish diaspora came into existence (sometimes voluntarily) as a result of Israelites and Jews emigrating before the onslaught of invading armies; because of forced deportations; or because of enslavement, including the Assyrian captivity and the Babylonian captivity. Some Jewish families or even some whole Jewish communities were forced to relocate on a near-consistent basis because of anti-Jewish persecution, while many were wiped out entirely. Although some form of contact had been maintained between most of the mainstream Jewish diaspora communities over the millennia, contact had been lost with some of them, and as a result, they came to be regarded as lost by mainstream Jewry.

Women in Judaism have affected the course of Judaism over millennia. Their role is reflected in the Hebrew Bible, the Oral Law (the corpus of rabbinic literature), by custom, and by cultural factors. Although the Hebrew Bible and rabbinic literature present various female role models, religious law treats women in specific ways. According to a 2017 study by the Pew Research Center, women account for 52% of the worldwide Jewish population.

Gender has a bearing on familial lines: in traditional Rabbinic Judaism, Jewish affiliation is passed down through the mother, although the father's name is used to describe sons and daughters in the Torah and in traditional Hebrew names, e. g., "Dinah, daughter of Jacob".