why should the Quran get into such a specific on embryology or any other field for that matter? It is meant to ask you to reflect not memorize multiple tissues derived from all three germ layers for your board exams.
Come on, that is absurd...
I don't particularly care to dwell on the science of the Quran, the poetry of the Quran, the numerology of the Quran, the rules of grammar in the Quran, the biblical stories in the Quran, the prophetic signs of the Quran, the laws of inheritance in the Quran, the rules of economics in the Quran, how to establish a Govt. in the Quran.. then you'll have missed the point of what it is all about. It is meant as a guidance and a counsel for how you should live your life.. and it does it on many levels.. it need not be any more clear or any more vague than what it is. There will be those completely satsifed with the book and there will be those who always want to split hair..

I think that too is part of its intrigue, as their are verses to denote some will indeed question 'what did God want with that allegory'?..
each will make of it what he/she will.. and there will come the day when we shall all find out the truth, one way or the other..

peace