No, it's not a cheap sci-fi movie. Research into the microbial communities within and on us has shown that there are 10 times more microbial cells than human cells associated with the human body.
http://www.npr.org/templates/story/stor ... =129862107
There are trillions upon trillions of microbes living on and in the human body.
To put this in perspective, Jeffrey Gordon, a professor at the Washington University in St. Louis School of Medicine, who studies the microbes that live on and in us, offers this factoid: "We think that there are 10 times more microbial cells on and in our bodies than there are human cells. That means that we're 90 percent microbial and 10 percent human. There's also an estimated 100 times more microbial genes than the genes in our human genome. So we're really a compendium [and] an amalgamation of human and microbial parts."
Gordon's research shows that these microbes living in our bodies aren't just there for the ride — they're actively contributing to the normal physiology of the human body. He points to the trillions of microbes that live in our gut, doing everything from encoding enzymes to serving as pathways for vitamin production to digesting the parts of food we can't digest on our own.
"We're trying to understand how these compendia of microbes operate as a community — how they are shaped by the habitats in which they live and, in turn, how they shape us," he says. "To what extent can we attribute different aspects of our physiology to our microbial communities? If a person has a physiological state — if they're obese or if they have diseases like inflammatory bowel disease — how much of that disease is attributable to their microbial communities, and how can we establish that relationship?"