To what extent is the scientific validity of what was mentioned in the hadiths about the effect of the man's or woman's fluid preceding the other's in determining the child's resemblance to the paternal or maternal uncles and aunts, and does that contradict Mendel's laws of inheritance, and what is meant by "preceding" and "the woman's fluid" in the hadiths?

The matter in its origin is related to the cause of resemblance in the child. In the noble prophetic hadith: "If the man's fluid precedes, the resemblance is his. And if the woman's fluid precedes, the resemblance is hers." There are other hadiths that clarify that the man's fluid is white and thick, and the woman's fluid is yellow and thin, and whichever prevails (precedes) determines the resemblance and the gender (masculinity or femininity).

Al-Hafiz Ibn Hajar explained these hadiths in "Fath al-Bari," clarifying that "preceding" here means "precedence," which is a spiritual precedence, and that the precedence that causes resemblance is according to abundance.

From a scientific perspective, there is still ongoing research regarding the woman's fluid and its role in formation. As for resemblance, it is probable that the hadiths refer to what science calls the prominence and aggressiveness of genes, which explains the child's resemblance to their mother and maternal uncles, or to their father and paternal uncles.

It must be noted that the prophetic statement expresses phenomena using the terminology of its era, in a manner consistent with the people's understanding at that time, with the possibility of its alignment with modern scientific explanations without contradiction. For Sharia is not a book of natural science; rather, it is a book of guidance and legislation.