Title: Qasim ibn Muhammad ibn Abi Bakr
Content:  Al-Qāsim's father was Muhammad, son of the first Rashidun Caliph, Abu Bakr. His paternal aunt was Aisha, one of the wives of the Islamic prophet Muhammad. Some traditions state that Al-Qāsim's mother was a daughter of Yazdegerd III and a sister of Shahrbanu, the mother of fourth Shi'a Imam, Ali ibn Husayn. Al-Qāsim married Asma, a daughter of his paternal uncle Abdul-Rahman ibn Abi Bakr. They were the parents of a daughter, Umm Farwah. The latter later married Ali's son Muhammad al-Baqir and became the mother of the sixth Shi'a Imam, Ja'far as-Sadiq. Al-Qāsim also had a son named Abdur-Rahman.
Title: Qasim ibn Muhammad ibn Abi Bakr
Content:  Al-Qāsim ibn Muhammad ibn Abī Bakr (قاسم بن محمد) (born 36 or 38 AH and died 106 AH or 108 AH; corresponding to c. undefined 660/662 and 728/730) was an important jurist in early Islam. In the Naqshbandi Sufi order (originated in the 14th century) he is regarded as a link in the Golden Chain, in which he was purportedly succeeded by his maternal grandson Ja'far al-Sadiq.
Title: Qasim (name)
Content: Qasim ibn Muhammad (died 605), son of Muhammad and Khadijah bint Khuwaylid ; Qasim ibn Muhammad ibn Abu Bakr (died ca. 728), jurist in early Islam ; Qasim ibn Hasan (ca. 666–680), son of Hasan ibn Ali and grandson of Muhammad 
Title: Muhammad ibn Abi Bakr
Content:  Muhammad ibn Abi Bakr was born in 631 to the first caliph Abu Bakr and his third wife Asma bint Umays. After Abu Bakr's death, Asma married Ali ibn Abi Talib, and thus Muhammad ibn Abi Bakr became the adopted son of Ali. Muhammad ibn Abi Bakr had a son named Qasim ibn Muhammad ibn Abi Bakr. Qasim ibn Muhammad ibn Abi Bakr's wife was called Asma and she was the daughter of Abdul-Rahman ibn Abi Bakr who was Abu Bakr's eldest son. The daughter of Qasim ibn Muhammad ibn Abi Bakr and Asma was called Umm Farwah, who was the mother of Ja'far al-Sadiq.
Title: Qasim ibn Muhammad ibn Abi Bakr
Content:  Aisha lived a very long time and taught her nephew Qasim ibn Muhammad ibn Abi Bakr. Many Hadith are quoted through Qasim. Al-Qāsim ibn Muhammad ibn Abi Bakr was one of the seven most famous jurists in Medina, and was considered as the most knowledgeable among them. He was highly influential in disseminating early traditions of hadith, fiqh (jurisprudence) and tafsir (exegesis) of the Qur'an. He was a pious imam and was very knowledgeable in the narration of the Traditions. Abu Zannad said, "I never saw anyone better than him in following the Sunnah of the Prophet (s). In our time no one is considered perfect until he is perfect 
Title: Qasim ibn Muhammad
Content:  Qasim ibn Muhammad (قاسم بن محمد) was the eldest of the sons of Muhammad and Khadija bint Khuwaylid. He died in 601 CE (before the start of his father's prophethood in 609), after his third birthday and is buried in Jannat al-Mu'alla cemetery, Mecca, Saudi Arabia.
Title: Abu al-Qasim
Content:  The name Abu al-Qasim or Abu'l-Qasim (أبو القاسم), meaning father of Qasim, is a kunya or attributive name of Islamic prophet Muhammad, describing him as father to his son Qasim ibn Muhammad. Since then the name has been used by the following:
Title: Qasim ibn Abbas
Content:  Qasim ibn Abbas (قَاسِم ٱبْن عَبَّاس); although there is not such name (Qasim) as a son of Abbas ibn Ali in old sources, some sources regard him among the martyrs of Karbala. According to some sources, Qasim ibn Abbas was the son of Abbas ibn Ali and his mother was Lubaba bint Ubaydillah. He and his brother al-Fadl ibn al-Abbas died in the Battle of Karbala.
Title: Qasim ibn Hasan
Content:  Qasim was born the son of Hasan ibn Ali, the second Imam, and his wife Umm Farwa. His father was the elder son of Ali ibn Abi Talib and Fatimah, and Qasim was thus a great-grandson of the prophet Mohammad, father of Fatimah.
Title: Qasim ibn Muhammad ibn Abi Bakr
Content:  Al-Qāsim ibn Muhammad ibn Abī Bakr was born on a Thursday, in the month of Ramadan, on 36 / 38 AH (approximately).

Question: Who is the father of Qasim ibn Muhammad ibn Abi Bakr?
Answer: Muhammad ibn Abi Bakr.
محمد بن أبي بكر.