If you think about it, a newly formed zygote/ early term foetus would resemble a clot of blood were we to examine one with the naked eye and presumably there were plenty of early births and miscarriages in 7th century Arabia upon which Mo could have based his theory behind verse 23:14.
seems to me that muhammad got it wrong cause a clot is a
semisolid mass, therefore a clot of blood is a semisolid mass of blood and a zygote is a cell which does not look like a clot of blood at all, it is transparent, like any oter cell. Don't believe me? look it up. seems to me that muhammad give a poor figure of speech.
I can provide a link that gives a picture of a zygote though i didn't read the website
here:
http://www.midwestivf.com/art/zift.htm