It sounds crazy, but our obsession with cleanliness may be making us sick. Doctors say trying to remove all bacteria and germs from our kitchens and bathrooms weakens -- not strengthens -- our immune systems.

Dr. Ambro Van Hoof is a microbiologist at Houston's UT Health Science Center. He says we have more bacteria cells than human cells in our bodies.

"Every healthy person has a lot of bacteria in them and on them, especially in the gut."

Dr. Van Hoof says moving to an urban jungle has not improved our health. He says we were better off in decades past in an agriculture-based economy.

"As people moved away from farms, where they were exposed to lots of germs to cities where they were exposed to a lot fewer germs."

Dr. Van Hoof says if you want to obsess about something, focus on the sponges you use to wash dishes. They're breeding grounds for mold and bacteria.