Qureshi (2011, Reproductive Physiology of Domestic Animals) included Qur’anic wisdom in his book on reproductive physiology. The Qur’an states, sex of mammalian progeny is determined by the male or female sex chromosome bearing spermatozoa. X bearing spermatozoon will give rise to female young one, if it fertilises the ovum. A Y bearing spermatozoa will lead to birth of a male young one.

According to the Qur’anic verse: “That He created the pairs, male and female from a fluid drop sperm, as it is emitted.”(Qur’an 53:45-46)        

It confirms that man’s sex is determined at the time of semen ejaculation. Prophet Muhammad (s) told the people that the sperm, nutfa, was responsible for determining the sex of young one (through X or Y bearing spermatozoa).

Scientists have discovered very recently that sex of an embryo is determined by the type of spermatozoa fertilising the ovum and sperm is a cell found in the ejaculated semen.

On the one hand the whole world was not aware of the fact that semen determines the sex of the young till the beginning of the 20th Century (Mittwoch 2005). On the other hand, the Qur’an narrated the story very clearly 14 centuries earlier.

Spermatogenesis takes place in the testicles, which are a continuation of gonocytes, originating near the kidneys, located at the back and then migrating down to the abdominal cavity at the end of pregnancy.

The Qur’an has stated it thus: “And remember when your lord brought forth from the children of Adam, from their lions, their seeds.” (Qur’an, 7:172)

The origin of progeny has been at the region of the back which is the site of formation of embryonic testicles. 

The bi-potential gonad is the common precursor of mammalian gonads,during embryogenesis. It possesses the capacity of developing into either testis or ovary. Generically, sex is determined during fertilisation as an ovum can either be fertilised with Y or X bearing spermatozoa, leading to formation of male or female embryos.

However, the bipotential gonad still retains the capacity to lead to formation of testis or ovary and it is driven by the presence of Y chromosome and the expression of Y linked Sry gene. The Sry gene in the male embryos stimulates the cascade of events which leads to development of testis and suppression of ovarian development. In the female embryos the Sry gene is absent and the bi-potential gonad converts into ovary.

After conception the male and female embryonic genital ducts (Wolffian and Mullarian ducts) are found in the bi-potential gonads up to 11th day. With the expression of Sry gene, the bi-potential gonad develops into testis and endocrine hormones are produced, leading to regression of Mullarian ducts and subsequently the Wolffian ducts develop into epididymis, vas deferens, seminiferous tubules and testicular descent.

In female embryos the absence of Sry genes leads to development of the female reproductive tract and endocrine hormones to be secreted by ovary. Partial expression of Sry genes give rise to development of rudimentary sexual organs of both sexes and individual comes as hermaphrodite.

Qur’an mentions the sex differentiation in mammals during embryogenesis, as transformation of alaqa into mudgha, in a rapid way completing in two days, 24th and 26th day post-conception. The rapid change has been expressed with the word “fa” meaning “then” and pointing at the rapid development of transformation.

Qur’an says: “Then We changed the alaqa, leach like clot, into a mudgh, chewed lump.” (Qur’an, 23:14)

We observe different conjunctive articles which reflect the difference in embryonic stages. The alaqa has been mentioned as the second stage in embryonic development and described in several verses.

The Almighty says in the Qur’an: “Was he not a drop of semen emitted? Then he became a leech-like clot, then did Allah make and fashion him in due proportion”. And of him He made two sexes, male and female.” (Qur’an, 75:37-39)