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What kids should know about why people get birthmarks

Sisters with salmon patches

Sometimes, a birthmark runs in a family like this salmon patch, which has nearly faded on the older sister.

Sisters with salmon patch birthmarks

Do you ever wonder why people get birthmarks? Good question. 

Some types of birthmarks run in families, but not always. Nobody really knows why babies get them or why some kids have small birthmarks and others have bigger ones. They just seem to happen.

We still don’t know exactly why birthmarks develop, but here’s what scientists have learned so far.

The cause varies with the type of birthmark. Some birthmarks form when blood vessels do not form properly.

Other birthmarks appear when cells that give our skin color, melanocytes (meh-lan-oh-cites), clump together. That’s why newborns develop moles or café-au-lait spots.

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