As I say in my book, we are hurting ourselves by keeping homes that are too clean. People clean their countertops with antibacterial sprays, they use alcohol on their hands, and they shower with antibacterial soaps. Some folks argue it's hard to prove that this over cleanliness is responsible for illnesses.

Recent research though has conducted a natural experiment on this topic. By natural experiment they mean something that just happens without a researcher having to set it up. The research concerns the impact of having a dog on the health of children in the home. Why this is a natural experiment connected to over cleanliness is that, as anybody who's ever owned a dog knows, they get dirty when they go outside. The research shows that families with dogs who spend the greatest amount of time outdoors have the fewest number of respiratory ailments. In other words, families who unconsciously bring germs into their homes (on their dogs) are more healthy than families either without dogs or whose dogs don't go outside.

What this research is saying is stop cleaning your house so much. People need to interact with bacteria, viruses and other "yucky things."

Tomato growers have inadvertently made their product almost tasteless. The problem is a result of an unintended consequence. In an effort to make their product visually more appealing to consumers, growers manipulated the genetic structure of tomatoes such that all tomatoes tend to look alike and have a color that consumers are looking for. There's no question that these tomatoes have an industrial look - sort of like new Toyota Camry's - but that quality evidently appeals to the mass of consumers.

The unintended consequence of this scientific effort to create a more marketable tomato has been to turn off the gene in tomatoes that gives them their characteristic flavor and aroma. In other words, consumers are now eating beautiful tomatoes that have no taste. No wonder heirloom tomatoes are so popular and so expensive.

We are told that growers will once again manipulate their tomatoes genetic structure to turn back on the taste and aroma gene. Let's hope there's not another unintended consequence that results from this action such as one that would make consumers sick or that would leave a nasty stain on your counter after cutting them.