A useful place to begin is the material out of which we are created. There are several statements which speak figuratively of man being brought forth from the earth, from clay, mud, water or dust, or even from nothing (see Sura 11:61, 19:67, 23:12, 25:54, 30:20, 32:7). These verses demonstrate that a wide variety of substances are claimed to have given rise to human life. A recurring theme is the creation of man from a drop of fluid (semen), as the following example shows:
16:4 - He created man from a drop of fluid (see also 32:8, 53:46, 56:58, 75:37, 76:2, 80:19, 20)
We must ask if seventh-century Muslims at the time of Muhammad could have known this. In Genesis 38:9 the Bible tells us that Onan 'spilled his semen on the ground to keep from producing offspring for his brother'. This predates Muhammad by centuries and does not prove divine authorship, as it is simply a direct observation of what is released in the act of sexual intercourse.
In Sura 86:6,7 we read:
He is created from a gushing fluid that issued from between the loins and ribs
In this verse, semen is apparently coming out of the area around the kidneys and back, which is a real problem for we now know that the testicles are the site of sperm production. Muslims maintain that this verse is indicating the embryological development of the testicles in the renal area before their subsequent descent into the scrotum. However, the verse states that it is the fluid rather than its organ of production that comes from this area. A delve into Greek literature reveals some interesting clues as to the origin of this idea.
The Greek physician Hippocrates taught in the fifth century BC that semen comes from all the fluid in the body, diffusing from the brain into the spinal marrow, before passing through the kidneys and testicles into the penis. This teaching was well-known in Muhammad's day, and may well explain why the Qur'an contains such an erroneous statement.
Sura 23:13-14 states that God places us 'as a drop (of seed) (nutfah) in a safe lodging; then fashioned from the drop a clot (alaqa), then fashioned from the clot a little lump (mugdah), then fashioned from the little clot bones, then clothed the bones with flesh, and then produced it as another creature'. 75:38 also says man becomes an alaqa and 96:2 says we came from alaq. We have to ask what the precise meaning of these words is in order to know whether or not the verses contain important scientific statements as Moore and others have claimed.
The use of nutfah elsewhere (e.g. 16:4, 18:37, 23:13, 35:11, 53:46, 75:37, 76:2, 80:19) makes it clear that it refers to semen. It is harder to understand what alaqa means, and many different suggestions have been made: clot, small lump of blood, leech-like clot, and 'leech, suspended thing or blood clot' (Moore, op cit). The most widely accepted translation of alaqa is 'clot', but this is impossible, since there is no stage at which the embryo consists of a clot. Moore claims that it means 'leech', and goes on to argue that a 24-day old embryo resembles a leech in its appearance. In a hadith (or Muslim tradition), however, Muhammad claimed that the alaqa referred to the embryo between days 40 and 80. The third stage, mugdah means a morsel of flesh, and according to Muhammad refers to the embryo between days 80 and 120, when the embryo is actually much bigger than a bite-sized peice of flesh!
In fact the account of the different stages in embryology as described by the Qur'an is virtually identical to that taught by Galen, writing in Turkey around 150 A.D, who taught that the embryo developed in four stages. The first is an unformed white conceptus like semen, the second a bloody vascularised foetus, the third when other features are mapped out but not fully formed, and the fourth when all the organs are well formed and joints freely moveable. Either the author of the Qur'an knew this when writing the Qur'an, or else he was describing the clot which appears when a woman is having a miscarriage. Since we know that Muhammad had at least nine wives this is entirely possible, but it does mean that the alaqa is not the stage of embryological development that some would have us believe.
Much of the embryology in the Qur'an and Hadith can be traced directly back to the ancient Greeks. For example there is a hadith in which Muhammad says 'If a male's fluid prevails upon the female's substance, the child will be a male by Allah's decree, and when the substance of the female prevails upon the substance contributed by the male, a female child is formed.' Muslims claim that this refers to X and Y chromosomes which determine the sex of an infant. A far more likely suggestion is that this is simply a reflection of the incorrect belief of Hippocrates that both men and women produce both male and female sperm, and the resulting sex of the child is determined by which sex's sperm overwhelms the other in strength or quantity.
It is one thing for the ancient Greeks to be teaching all this, but how do we know that the material was familiar to the Arabs of Muhammad's day? Ali at-Tabari's 'Paradise of Wisdom', written in about 850 AD, says that he was following the rules set down by Hippocrates and Aristotle when he wrote his treatise. The intelligentsia of Muhammad's time were very familiar both with Greek and Indian medicine. Indeed, a major work on the history of embryology which is cited in the references in The Developing Human devotes over 60 pages to ancient Greek embryology and less than one page to Arabic embryology, concluding that the Qur'an is merely 'a seventh-century echo of Aristotle'. It is hardly surprising that the Islamic version of Prof Moore's book is not listed on the British Library catalogue and cannot be found in medical school libraries either in Britain or the US.
In conclusion then, there is not a single statement contained in the Qur'an relating to modern embryology that is not either scientifically incorrect or which was well known through direct observation by the ancient Greek physicians many centuries before the Qur'an was written. Far from proving the alleged divine credentials of the Qur'an, its embryological statements actually provide evidence for its human origins.
This article borrows from a much fuller account of the subject, which is available on the Internet at answering-islam.org.uk/Quran/Science/embryo.html