The study looked at whether the amount of a specific type of bacteria in newborn babies' poop, called Bifidobacterium longum subspecies infantis (B. infantis), affects their growth and health in the first 6 months of life. The researchers studied almost 1000 babies in Bangladesh and found that the level of B. infantis in their poop was not linked to how much they grew or their risk of getting sick. This suggests that increasing B. infantis in babies' guts may not help improve their growth in populations where babies often struggle to grow after birth.