I just went back and listened to this interview I did on “Radiolab” with Robert Krulwich a couple years ago. It’s about the life within us. I led Robert on a quick tour through our gut, stopping to describe a few of the many species that lurk inside our bodies.

It all still holds true, I think–except for one thing I say at 3:02.

It’s at that point that I say that in the womb, we’re sterile. Only as we’re being born, I inform Robert, do we start to getting inoculated with microbes.

I thought I was right at the time. Scientist after scientist told me that. I read it in scientific reviews.

But now a number of scientists are having some serious