Hey Mike! Those are great comments and suggestions. As far as changing the title goes, it's a bit late for that and I'm not sure it's necessary! And while the Walter group does not establish the existence of a fetal microbiome, they put forth a pretty strong case for it being a highly unlikely probability. As I mentioned in the post, models are scientists' ways of dealing with these kinds of problems. How many fetuses would we have to sample to "prove" that there is no such thing as a fetal microbiome? So my current model is "Fetal microbiomes are a myth".
But you're absolutely right! Currently, there is no compilation of data that outright rejects the possibility of a fetus possessing a microbiome prior to birth.
There is also strong evidence, which I didn't talk about in this article, for the very rapid establishment of a microbiome in the newborn after birth. Especially if it is nourished with breastmilk from the mother or a surrogate.
So thanks for the compliments and I look forward to future conversations :)