Birthmarks can be found on over 80 percent of babies, according toBabyCenter.

These marks are either present at birth or develop within a few months of a baby being born.

These seemingly simple patches of skin have a lot more to them than meets the eye, though.

Baby with birthmark

The second major category of birthmarks consists of pigmented patches of skin.

These pigmented birthmarks include cafe-au-lait spots and Mongolian spots.

Moles that develop later in life are just moles and are not considered to be birthmarks.

Woman with port wine stain

Moles can also be split into two broad categories of their own: flat and raised.

That explains how birthmarks get their color, but what causes them to form?

Others think that placenta-produced proteins might increase the chances of developing certain birthmarks.

Birthmark on neck

None of these theories have been proven, however.

One of the most enduringmythsabout birthmarks links pregnant mothers with these mysterious marks.

This legend persists in several countries including Israel, Egypt, Brazil, and Italy.

pregnant woman

One of the major birthmarks that typically disappears as a child ages is the Mongolian spot.

Mongolian spots almost always completely disappear by the time a child is 5 years old.

Strawberry birthmarks are another key in of birthmark that typically fades as a child gets older.

Baby with Mongolian spot

Birthmark removal isn’t always for aesthetic purposes, though.

Some types of birthmarks that form on the scalp can lead to a bald spot, prompting removal.

Moles are another key in of birthmark that are often surgically removed.

Laser removal of birthmark

Some deep hemangiomas can damage the skin around them.

Sometimes, though, birthmarks can be an indicator of a disease.

Woman’s Daynotes that you should always monitor moles and birthmarks for signs of change.

Girl with birthmark

If you see anything unusual, youshould make an appointment with your doctor.

Some types of birthmarks may run in families

Birthmarks aren’t hereditary… usually.

Again, science can’t give us many answers here.

Baby with birthmark

“Some birthmarks run in families,” Dr. Hardick Soni toldInsider.

This less-than-satisfying answer confirms again just how mysterious birthmarks truly are.

Hereditary birthmarks play a key role inancient Greekliterature.

Woman with birthmarks

According to the myth, Seleucos passed this birthmark on to his descendants.

Birthmarks have sometimes been associated with evil

Some of the many superstitions surrounding birthmarks are downright sinister.

A birthmark could be all the proof that was needed to condemn someone as a witch.

Baby with birthmark

Hopkins' guide resulted in hundreds of deaths both in England and in the Americas.

Another belief says that if a baby has a mole, they will be successful in the future.

This theory isn’t just rooted in superstition, either, but has actually been scientifically examined.

Child with birthmark

For Stevenson, this was indisputable proof of reincarnation.

According toMedical News Today,birthmarks can affect the hair, sometimes causing a white lock of hair.

These locks of white hair can run in families.

Woman with long hair

Barnes is one of about 40 people in his family to have this distinguishing mark.

“It runs through my family,” said his mother.

“We don’t know where it originated but my grandmother had it as did her grandparents.”

Eye birthmark

Worthy’s mother and grandmother also have a white streak of hair.

Many people don’t know they have them and they’re typically discovered by doctors during eye exams.

The practice of telling mole-based fortunes is called moleomancy.

Woman with moles

If you have one with angular sides, molemancy suggests that you have a “fiery temper.”

According toThe Encyclopedia of Superstitions,the practice is also referred to as molescopy.

The placement of moles can supposedly reveal a lot about a person.

Birthmark on arm

If you have moles on your ears, you will one day become wealthy.

A mouth mole indicates someone who is full of passion.

If there are many moles on your breasts, it means you’ll one day have many children.

Moles on your buttocks indicate a lazy nature.

A birthmark appearing on the face is considered to be a sign of beauty.