The narration concerning how the resemblance comes about:

… َهَلْ يَكُونُ الشَّبَهُ إِلاَّ مِنْ قِبَلِ ذَلِكِ إِذَا عَلاَ مَاؤُهَا مَاءَ الرَّجُلِ أَشْبَهَ الْوَلَدُ أَخْوَالَهُ وَإِذَا عَلاَ مَاءُ الرَّجُلِ مَاءَهَا أَشْبَهَ أَعْمَامَهُ ‏”‏

… In what other way does the resemblance come about except for the fact that when the genes contributed by woman prevail upon those of man, the child resembles the maternal family, and when the genes of man prevail upon those of woman the child resembles the paternal family.

Reported by Muslim on the authority of Aisha, may Allaah be pleased with her.

A narration

reported by Ibn Maajah on the authority of Anas bin Malik that the Prophet صلى الله عليه وسلم said:

فَأَيُّهُمَا سَبَقَ أَوْ عَلاَ أَشْبَهَهُ الْوَلَدُ

“Whichever of them comes first or predominates, the child will resemble (that parent).”

A narration concerning what causes by the permission of Allah for the fetus to be a girl or boy:

قَالَ جِئْتُ أَسْأَلُكَ عَنِ الْوَلَدِ قَالَ ‏”‏ مَاءُ الرَّجُلِ أَبْيَضُ وَمَاءُ الْمَرْأَةِ أَصْفَرُ فَإِذَا اجْتَمَعَا فَعَلاَ مَنِيُّ الرَّجُلِ مَنِيَّ الْمَرْأَةِ أَذْكَرَا بِإِذْنِ اللَّهِ وَإِذَا عَلاَ مَنِيُّ الْمَرْأَةِ مَنِيَّ الرَّجُلِ آنَثَا بِإِذْنِ اللَّهِ ‏”‏ ‏.‏ قَالَ الْيَهُودِيُّ لَقَدْ صَدَقْتَ وَإِنَّكَ لَنَبِيٌّ

“If the male’s substance prevails upon the female’s substance, it is the male child that is created by Allah’s Decree, and when the substance of the female prevails upon the substance contributed by the male, a female child is formed by the Decree of Allah. The Jew said: What you have said is true; verily you are an Apostle… “

Reported by Muslim on the authority of Thaubaan, may Allaah be pleased with him.

However, this narration has been disputed by some scholars and they have mentioned the role of the child being a boy or girl doesn’t have any natural causes.

Mentioned by

AbdulFattaah Bin Uthman
Abu Fajr