According to the British paper The Daily Telegraph, Mahmoud Ahmadinejad comes from a Jewish family that converted to Islam after he was born.
Update: However, The Guardian has refuted this claim.
UPDATE: I apologize for spreading a false rumor in the original version of this diary (not to mention that the subject had already been diaried).
Here's part of what the Guardian says:
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.
The original story said that a photo of Ahmadinejad holding up his identity papers shows that his original family name was Sabourjian, which known in Iran as a Jewish name.
The Sabourjians traditionally hail from Aradan, Mr Ahmadinejad's birthplace, and the name derives from "weaver of the Sabour," the name for the Jewish tallit shawl in Persia. The name is even on the list of reserved names for Iranian Jews compiled by Iran's Ministry of the Interior.
He has said that his family changed its name when they moved to Tehran when he was four years old, but he never has said what it was changed from or why.
During this year's presidential debate on television he was goaded to admit that his name had changed but he ignored the jibe. However Mehdi Khazali, an Internet blogger who called for an investigation of Mr. Ahmadinejad's roots, was arrested this summer.