AFAIK it all boils down to the fact that during embryonal development our cells, which at that point were just a blob of undifferentiated autonomous chemical machines, somehow managed to unanimously agree upon the cardinal directions (up-down, left-right, front-back) for future development - and thanks to this, we don’t have toes growing out of our ears.
You know that we’ve gestated various animals in weightless conditions on the ISS, yes? They look normal.
We have? Do you have a source for that? That would be amazing. :)