I have what are called "Liver spots," how did I get them?

Definition:
Liver spots are flat brown-black spots that usually occur in sun-exposed areas of the body. They are also called age spots. They are unrelated to the liver or liver function.

Alternative Names:
Sun-induced skin changes - liver spots; Senile or solar lentigines; Skin spots - aging; Age spots
Causes, incidence, and risk factors:
Liver spots are changes in skin color associated with older skin. The increased pigmentation may be brought on by aging, exposure to sun or other forms of ultraviolet light, or other unknown causes.

Liver spots are extremely common after the age of 40. They occur most often on the backs of the hands, on the forearms, shoulder, face, and forehead, areas of highest sun exposure.

They are harmless and painless, but they may affect the cosmetic appearance. Occasionally, liver spots may obscure the diagnosis of skin cancers.

Symptoms:
The main symptom is a skin lesion that is a painless, flat patch or macule (area of skin color change):


Usual color: light brown to black
Usual location: hands, arms, or forehead

Signs and tests:
A diagnosis is based on the appearance of the skin, especially if the patient is over 40 and has had a lot of sun exposure over the years.

Treatment:
No treatment is needed in most cases. The cosmetic appearance of your skin may be improved by the use of skin bleaching lotions or creams. Cryotherapy (freezing) or laser treatment may be recommended to destroy the liver spots.

Expectations (prognosis):
Liver spots are not medically dangerous. They are permanent skin changes that may affect the cosmetic appearance of the skin.

Complications:
A possible complication is emotional distress from the appearance of the liver spots.

Calling your health care provider:
Call for an appointment with your health care provider if liver spots are present and removal is desired, or if any new symptoms develop, particularly changes in the appearance of any skin lesion.

Prevention:
Protect your skin from the sun by taking the following precautions:

Wear protective clothing such as hats, long-sleeved shirts, long skirts, or pants.
Use sunglasses to protect the eyes.
Sunlight is most intense at midday, so try to avoid exposure during these hours.
Use high quality sunscreens, preferably with SPF (sun protection factor) ratings of at least 15. Apply sunscreen at least a half hour before exposure, and reapply frequently. Use sunscreen in the winter, too.

genetics mostly. Your mom or dad probably had them too.

Leo gave you some great information. Remember to prevent them always use sunscreen.