We've all grown up hearing all sorts of wives' tales. Some of them seem to make good sense, but a lot turn out to be just nonsense.
We've investigated 10 more commonly held beliefs in our latest myth-busting segment — some that you suggested to us on our "20/20" Web site.
Here's what we found out.
MYTH #10 — A Full Moon Causes Strange Things to Happen E-mail suggestion from Pamela Bartlett of Danvers, Mass.
Lots of people believe that when the moon is full, weird things happen.
Nurses told us their hospital becomes "like a zoo," and police officers told us there are "more lunatics out on the street" during a full moon.
Mitchell Lewis, an astrologer, said, "I warn everybody to be careful around the three days of the full moon."
People pay him for advice like that.
So many people believe the moon changes us, yet Michael Shermer, editor of Skeptic magazine points out that some 36 studies have been conducted on whether there's a full-moon effect. They found nothing.
"No more emergency room visits. No more babies born. No more psychiatric admissions, nothing," Shermer said.
This is embarrassing to me, because in 1984, I reported that a study of murders in Dade County found that more murders were committed during full moons than at any other time.
"Researchers went back, re-analyzed the data, and discovered that there's nothing unusual going on. It's pure chance," Shermer said.
Why do so many of us think weird stuff happens when the moon is full? Because our memory is faulty. We look for patterns, and if we find one, it stays in our brain.
Shermer explained it this way: "We don't remember the unusual things that happen on all the other times, because we're not looking for them. These things go on all the time. And there's no full moon. … We remember the hits, we forget the misses."
MYTH # 9 — You Don’t Gain Weight on Low-Carb Foods?
If you allow yourself to indulge in the hundreds of tempting new products on the supermarket store shelves and forget to count calories, you might be in for a shock.
"The tendency is for the consumer to say, 'oh, it's low-carb. Then it must be low in calories too,'" said Good Housekeeping's nutritionist, Delia Hammock. "That is a myth."
With the same desperation that fed the high-fiber or low-fat crazes, we're now chowing down anything that suggests low-carb, even though that term has never been precisely defined. We're in the midst of a supermarket free-for-all: The label might say "low-carb" or "net-carb" or "effective carb."
"They may be using sugar alcohols instead of regular sugars … They may add more fiber to it … a lot of times they will add soy flour." said Hammock. "They subtract the sugar alcohols, you know, and the fiber and some other things, maybe like glycerols … but your waistline isn't going to subtract those, and people need to understand that."
MYTH #8 — Do Girls Feel More Pressure to Have Sex Than Boys?
It's an image we've all grown up with. The good girl being pressured to go all the way. But contrary to what you may think, nowadays it's boys, not girls, who are feeling the most pressure to have sex, according to a recent study.
We spoke with a group of high school kids from New Jersey, who confirmed the findings of a surprising survey by the Kaiser Family Foundation. It says that 33 percent of teen boys report feeling pressure to have sex compared to only 23 percent of girls. Often it's the boys who put pressure on boys.