Take the panic over genetically modified organisms, or GMOs. Ninety percent of all corn grown in America is genetically modified now. That means it grew from a seed that scientists altered by playing with its genes. The new genes may make corn grow faster, or they may make it less appetizing to bugs so farmers can use fewer pesticides.
This upsets some people. GMOs are "unnatural," they say. A scene from the movie "Seeds of Death" warns that eating GMOs "causes holes in the GI tract" and "causes multiple organ system failure."
The restaurant chain Chipotle, which prides itself on using organic ingredients, produces videos suggesting that industrial agriculture is evil, including a comedic Web series called "Farmed and Dangerous" about an evil agricultural feed company that threatens to kill its opponents and whose products cause cows to explode.
Michael Hansen of Consumer Reports sounds almost as frightening when he talks about GMOs. On my show, he says, "It's called insertional mutagenesis ... you can't control where you're inserting that genetic information; it can have different effects depending on the location."
Jon Entine of the Genetic Literacy Project responds: "We've eaten about 7 trillion meals in the 18 years since GMOs first came on the market. There's not one documented instance of someone getting so much as a sniffle."
Given all the fear from media and activists, you might be surprised to learn that most serious scientists agree with him. "There have been about 2,000 studies," says Entine, and "there is no evidence of human harm in a major peer-reviewed journal."
That might be enough to reassure people if they knew how widespread and familiar GMOs really are -- but as long as they think of GMOs as something strange and new, they think more tests are needed, more warnings, more precaution.
Yet people don't panic over ruby red grapefruits, which were first created in laboratories by bombarding strains of grapefruit with radiation. People don't worry about corn and other crops bred in random varieties for centuries without farmers having any idea exactly what genetic changes occurred.
We didn't even know what genes were when we first created new strains of plants and animals. There's no reason to believe modern methods of altering genes are any more dangerous.
In fact, because they're far more precise, they're safer.
And since genetic modification can make crops more abundant and easier to grow, it makes food cheaper. That's especially good for the poor. Another life-changer is a new strain of vitamin A-enriched rice that has the potential to decrease the frequency of blindness that now afflicts about a half-million people a year, mostly children.
But activists -- who tend to be rich and well-fed -- are pressuring countries in Asia and Africa into rejecting GMO rice.
Crusades against food are endless. First Lady Michelle Obama urges students to eat organic, even though that term has no real meaning in science besides "partly composed of carbon."
My nonprofit for schoolteachers, Stossel in the Classroom, offers free videos that introduce students to economics. This year, we ran an essay contest inviting students to write on the topic "Food Nannies: Who Decides What You Eat?"
I was happy to see that many students understood that this debate is about more than safety. It's really about freedom. Sixteen-year-old Caroline Clausen won $1,000 for her essay, which contained this sarcastic passage: "Congress shall have the power to regulate the mixing, baking, serving, labeling, selling and consumption of food. Did James Madison's secretary forget to copy this provision into the Constitution?"
Rising generations will have more food options than ever before. They face less risk of starvation or disease than any humans who have ever lived. Let's give them science instead of scare stories.