Sheikh Hânî al-Jubayr, judge at the Jeddah Supreme Court
The child belongs to the husband and the adulterer has no right whatsoever to claim paternity.
We have the following hadîth related by `A’ishah:
`Utbah b. Abî Waqqâs requested from his brother Sa`d b. Abî Waqqâs to take away the son of Zum`ah’s wife, since `Utbah claimed that the child was not the son of Zum`ah, but actually his own son, by way of adultery.
Therefore, in the year of the conquest of Mecca, Sa`d took the boy claiming that the boy was his nephew and `Utbah’s son.
Zum`ah’s other son objected saying the boy was his brother and the son of his father’s wife and he was born on his father’s bed. Both of them arbitrated the matter to the Prophet (peace be upon him).
Sa`d said: “O Messenger of Allah, he is my nephew and my brother authorized me to place him under my custody.”
Zum`ah’s son said: “He is my brother and the son of my father’s wife and he was born on my father’s bed.”
The Prophet (peace be upon him) said to Zum`ah’s son: “He is yours.” Then the Prophet (peace be upon him) said: “The child belongs to the husband and the adulterer deserves nothing but to be stoned.”
[Sahîh al-Bukhârî (1948) and Sahîh Muslim (1457)]
Source: Islam Today