Old wives' tale

An old wives' tale is a wisdom much like an urban legend, supposedly passed down by old wives to a younger generation. Today old wives' tales are also common among children's peer sex education in school playgrounds. Old wives' tales often concern pregnancy, puberty and nutrition.

Some old wives' tales are true, and those that aren't often have roots in truth or are used to trick people into doing something.

Common old wives' tales

Eating carrots improves your night vision

Half-truth

Carrots do contain vitamin A, which helps to maintain healthy vision, but they do not contain enough to make any significant difference. This tale started in the Second World War when the British spread a rumour that their plane spotters were eating carrots to give them improved vision, concealing the truth about the invention of radar.

Having sex standing up is a contraceptive

False

This is an example of an old wives' tale in peer sex education. It may seem somewhat logical to a virgin but is not true. Sperm are capable of swimming up the vagina, through the uterus to the fallopian tubes, where they may fertilize an egg, regardless of how a woman is positioned during or after sexual intercourse.

Chocolate causes acne

False

Chocolate does not cause acne; in fact, there is little evidence that one's diet affects acne at all. This is an example of an old wives' tale used to discourage something (the large quantities of chocolate some children eat is unhealthy in other ways) by associating it with something that people are afraid of.

Masturbation causes blindness

False

Again, this is an attempt to discourage masturbation (usually among young males) by associating it with blindness. Masturbation in females is sometimes said to cause infertility; this is equally false.

Staying out in the cold without a coat causes pneumonia

False

Pneumonia is caused by bacteria such as Streptococcus pneumoniae. Variations on this tale include that someone who stays out in the cold will catch a cold (which is known to be caused by a virus).

This tale is one that took until fairly recently to debunk. As public awareness of the cause of disease increased, the tale evolved to include a number of different pseudoscientific explanations. One popular explanation is that a low core body temperature negatively impacts the effectiveness of the human immune system. This intuitively makes sense, as we know fever, an elevated core body temperature, is one of the immune system's defenses against infection, studies have shown that there is no statistical correlation between lowered core body temperature and decreased immune response. Still, this old wives' tale, in its modern, pseudoscientific version, is still prevalent.

Stepping on a rusty nail causes tetanus

It's neither the rust nor the nail

It is not the rust on the nail that is contributory, rather it is the nature of the wound. Any deep wound that heals over first at the surface can result in an infection protected from oxygen. Under such anaerobic conditions the tetanus bacterium can flourish in a person not appropriately vaccinated. The tetanus bacterium is commonly present both on skin and in soil. Before the availability of vaccine for tetanus the best treatment would be to keep the wound open so that it would heal from the bottom up.

Other old wives' tales

• Shaving/cutting hair makes it grow thicker than before.
• Having sex in a certain position increases or decreases the probability of fertilization/conception.
• Having a longer penis makes female sex partners feel better during sex or reach orgasm more easily. (common topic of e-mail spam messages)
• Eating the crust of bread makes your hair curl.
• A pimple on your tongue means that you have lied.
• If your chin does not shine yellow when you hold a buttercup underneath it then you do not like butter.
• Don't cross your eyes; they might stay that way.
• If you go swimming less than an hour after you've eaten, you'll get cramps.
• If you smell dandelions, you'll wet your bed.
• If you touch a toad, you'll get warts.
• If you feel a burning in your ears, it means that somebody is talking about you.
• Masturbation makes your hands hairy.
• If you sneeze suddenly, someone is talking about you behind your back or thinking about you.
• If a man has big feet, big hands, big ears, or a big nose, it means he has a big penis.
• Only homosexuals get HIV.