Babies who are breastfed have a different make up of gut microbes than those who are not due to the prebiotic qualities of breast milk. However, there are now some formula milks that contain prebiotics to support a baby’s gut in a similar way to breast milk. You’ll find more about this here.
How you’re born
The way you are born, whether vaginally or by caesarean is going to have an affect on your microbes. But the good news is there is plenty you can do to shape your microbes for the better.
By early childhood, your gut microbes become relatively stable but there are plenty of opportunities for the community of microbes to change along the way as we age. Read lots more on this here.