Prenatal development / Prenatal Life

There is some controversy about when the human Intestine / Gastrointestinal Tract (Gut / GIT) is first colonized, with recent studies reporting a placental microbiota and in utero colonization of the fetus

References:
Jiménez et al. 2008 Res. Microbiol. 159: 187-193
Aagaard et al. 2014 Sci Transl Med 6: 237ra265
Collado et al. 2016 Sci. Rep. 6: 23129

In contrast, others suggest that this evidence is limited by a lack of contamination controls, maintaining that the placenta and womb are sterile

References:
Lauder et al. 2016 Microbiome 4: 29
Kim et al. 2017b Microbiome 5: 52
Milani et al. 2017 Microbiol Mol Biol Rev 81: e00036-17
Perez-Munoz et al. 2017 Microbiome 5: 48
Lim et al. 20…