i have only hear the opposite. that the germs & bacteria thru the vagina are good for your babies, because since your baby being exposed to germs & bacteria at such a young stage, they already develop immunity hence their body is stronger. also, being born thru the vagina is apparently quite streefulf or the infant, hence babies born thru vaginal birth cope better with stress. there are studies to back these up, i'm sure you can google them.