Eggs have long been a symbol of fertility - think Easter baskets and ancient fertility rites of spring. The use of sparrow eggs as aphrodisiacs was prevalent in Ancient Greece (where that bird was associated with Aphrodite) and in India, where the Kama Sutra lists sparrow eggs as a potency builder. In many Asian countries, fertilized eggs are believed to strengthen the libido. The idea that eggs may be aphrodisiacs is not new, but the scientific evidence to support that idea is.

The first thing to consider: not all eggs are the same. Modern factory eggs are not fertilized by a cock; the hens are kept isolated from males. This makes the eggs last longer in storage and reduces the chance that the modern consumer will crack open an egg with blood in it. It also changes the chemistry of the egg - instead of a developing embyro that contains lots of natural hormones and growth factors, the egg contains simpler support nutrients.

Two doulbe-blind scientific studies conducted in Sweden using an extract from fertilized eggs were described in PMID:9100160. After two weeks, men receiving the fertilized egg extract were significantly more likely to report increased frequency of sexual intercourse, improved self-esteem, and greater stamina.

These two studies were relatively small, and no other researchers have tried to replicate them. But they are consistent with the traditional ideas on fertilized eggs. It isn't clear what the researchers used as a placebo - the ideal placebo would be an extract from non-fertilized eggs.

In Asia, fertilized eggs have long been regarded as aphrodisiacs and foods for convalescence. These are consumed in many countries in Asia, including Vietnam, China, and the Phillipines. In the Philippines, they are called balut. Balut is one of those foods like Scottish Haggis or Icelandic fermented shark that is talked about more than it is eaten. Balut eggs are usually from ducks. They are incubated and consumed 16-20 days after they are laid - the embyro has developed enough so that parts of the bird are evident ... beaks, wings, and other structures that make it crunchy.

The yuck-factor is high. You won't find balut in supermarkets or health-food stores. If you do find an Asian foodstore that carries them, the supply is often irregular, and they don't store well. So from a practical perspective, this is not an easy aphrodisiac. But if you are bold, you might be interested in trying this unusual food.

Eggs are a good source of cholesterol - the parent material for sex steroids like testosterone and estrogen. There is no doubt that excessive cholesterol in the blood is a risk factor for heart disease. But excessively low cholesterol can also be a problem, and the most recent research on eggs suggests that eating eggs in moderation does not increase the risk of heart disease.

Caviar is another type of egg that has a repuatation as an aphrodisiac. Whether or not it contains a significant amount of natural hormones or some other factor that can affect the human sex drive will be the subject of another page here at aphrodisiology.