Such differences in gut microbiome might be attributed to variations in several factors in study populations:—those that predate the pregnancy such as obesity, BMI, insulin sensitivity, adiposity, dietary habit, proinflammatory conditions, and ethnicity24, and those that arise in pregnancy such as weight gain and fetal factors (e.g., sex). The gene discussed is INS; the disease is obesity due to melanocortin 4 receptor deficiency.