Is Hitler Jewish?

Is Hitler Jewish? and Was Hitler Jewish? are two of the more common searches on Google believe it or not. Adolf Hitler was not Jewish.

According to Hitler's Wikipedia entry:

Hitler's father, Alois Hitler (1837–1903), was the illegitimate child of Maria Anna Schicklgruber. Alois's birth certificate did not list the name of the father, and the child bore his mother's surname. In 1842 Johann Georg Hiedler married Maria, and in 1876 Johann testified before a notary and three witnesses that he was the father of Alois. Nazi official Hans Frank suggested the existence of letters claiming that Alois' mother was employed as a housekeeper for a Jewish family in Graz and that the family's 19-year-old son, Leopold Frankenberger, had fathered Alois. However, no Frankenberger, Jewish or otherwise, was registered in Graz during that period. Historians now doubt the claim that Alois' father was Jewish; all Jews had been expelled from Graz under Maximilian I in the 15th century, and were not allowed to settle in Styria until the Basic Laws were passed in 1849.

An article on the Orthodox Union website claims that Hitler's nephew's grandson has converted to Orthodox Judaism and is a Jewish studies teacher in Israel.