That is indeed a miracle,if you are in the 21th century and still ignorant about it,you just believe without making any research by yourself.
It is the time to educate yourself and to know what flesh means
Please read
here
(Quran: Surah AI-Mu’minun,23:Ayat 12–14).
We (Allah) created man from a quintessence of clay. We then placed him as a nutfah (drop) in a place of settlement, firmly fixed, then We made the drop into an alaqah (leech like structure), and then We changed the alaqah into a mudghah (chewed like substance),then We made out of that mudghah, izam (skeleton,bones),then We clothed the bones with lahm (muscles,flesh) then We caused him to grow and come in being and attain the definitive (human)form. So, blessed be God, the best to create.
So if we arrange these stages chronologically we might come up with something like this
1.Nutfah amshaj (drop that is mixed) this stage covers the period from fertilization to implantation. This stage is further divided into: (present day germinal stage): Khalq, Taqdir, Harth.
2.Takhleeq (present day embryonic): this stage extends from the beginning of the 3rd week until the end of the 8th week and covers the developmental events. This stage is further divided into: Alaqah (leech-like)[1], Mudghah (somites)[2], Izam (skeleton)[3] and Laham (muscles)[4].
3.Nash”ah: (Growth) [present day Foetal stage] During this period the shaping and modelling are active,the external appearance develops in such a way that foetus becomes recognizably human.It lasts till the completion of pregnancy.It is further divided into: An-nashaa-Khalaqakha (from 9–26wks) and Al Hadana-al Rahamiya (from 26 wks to full term). This could be an apt way of classifying the various stages of human development. (3)
Please read in more details
Human Embryology and the Holy Quran: An Overview