Prophet Muhammad’s Children: How Many?
Question

How many daughters and sons did the Prophet (peace and blessings of Allah be upon him) have and from which of his wives (may Allah be pleased with them)?
Praise be to Allah.Prophet Muhammad (peace and blessings of Allah be upon him) had both sons and daughters , the first of whom was al-Qasim, from whom he took his kunya Abu’l-Qasim. He died in childhood, and it was said that he lived until he was old enough to ride. Then came Zaynab, and it was said that she was older than al-Qasim; then Ruqayyah, Umm Kulthum and Fatimah . 
It was said concerning each of them that she was older than her two sisters.
It was narrated from Ibn `Abbas that Ruqayyah was the oldest of the three and that Umm Kulthum was the youngest. 
Then ‘Abd-Allah was born to the Prophet (peace and blessings of Allah be upon him). There is some dispute as to whether he was born after the Prophet’s Prophethood began or before. Some scholars said that he was born after his Prophethood began. There is also some dispute as to whether he was al-Tayyib or al-Tahir, or whether they were other children; the correct view is that these were nicknames given to him; and Allah knows best. 
These children were all born from Khadijah and he had no children from any other wife. 
Then Ibrahim was born to the Prophet (peace and blessings of Allah be upon him) from his concubine Mariyah al-Qibtiyyah in 8 AH. (Zaad al-Ma’ad, 1/103) 
So the sons and daughters of the Prophet (peace and blessings of Allah be upon him) were all born to him from his wife Umm al-Mu’minin Khadijah (may Allah be pleased with her), apart from Ibrahim, who was born from the Prophet’s concubine Mariyah (may Allah be pleased with her), who was given to him as a gift by al-Muqawqis, the king of Alexandria and the leader of the Copts. 
According to the most correct opinion, the Prophet (peace and blessings of Allah be upon him) had seven children, three boys and four girls. The boys were: 

Al-Qasim
‘Abd-Allah
Ibrahim

And the girls were: 

Zaynab
Ruqayyah
Umm Kulthum
Fatimah

All of Prophet Muhammad’s (peace and blessings of Allah be upon him) children died during his lifetime, apart from Fatimah who died after him (peace and blessings of Allah be upon him).
And Allah knows best.