Maybe I spoke too soon in trying to be fair. The Ahmadinejad-Is-Jewish argument is hotly disputed here:
Upon closer inspection, a completely different interpretation of "Sabourjian" emerges. According to Robert Tait, a Guardian correspondent who travelled to Ahmadinejad's native village in 2005, the name "derives from thread painter sabor in Farsi a once common and humble occupation in the carpet industry in Semnan province, where Aradan is situated". This is confirmed by Kasra Naji, who also wrote a biography of Ahmadinejad and met his family in his native village. Carpet weaving or colouring carpet threads are not professions associated with Jews in Iran.
According to both Naji and Tait, Ahmadinejad's father Ahmad was in fact a religious Shia, who taught the Quran before and after Ahmadinejad's birth and their move to Tehran.
So religious was Ahmad Sabourjian that he bought a house near a Hosseinieh, a religious club that he frequented during the holy month of Moharram to mourn the martyrdom of Imam Hossein.
Moreover, Mahmoud Ahmadinejad's mother is a Seyyede. This is a title given to women whose family are believed to be direct bloodline descendants of Prophet Muhammad. Male members are given the title of Seyyed, and include prominent figures such as Iran's supreme leader Ali Khamenei. In Judaism, this is equivalent to the Cohens, who are direct descendants of Aaron, the brother of Moses. One has to be born into a Seyyed family: the title is never given to Muslims by birth, let alone converts. This makes it impossible for Ahmadinejad's mother to have been a Jew. In fact, she was so proud of her lineage that everyone in her native village of Aradan referred to her by her Islamic title, Seyyede.The reason that Ahmadinejad's father changed his surname has more to do with the class struggle in Iran.