It doesn’t take much to create a social media storm. But the subject of an online controversy in 2019 may have come as a surprise — it was about freckles.

European fashion company Zara used pictures of a Chinese model who had freckles — and social media users in China weren’t happy. They called it a false representation of Asian people.

Writing for CNN, Karoline Kan — herself a Chinese woman with freckles — said there are many in China who believe freckles are unattractive.

But for others, they’re just … freckles.

So what are freckles, and why do some of us have them?

Well, they’re small, flat, usually brown spots on the skin, and they’re mostly found on areas that are exposed to sunlight, like the face.

We aren’t born with freckles — they tend to develop in childhood. They may look darker in summer when people spend more time outside.

How do we get them?

People with fairer skin and red or lighter hair are more likely to have freckles — but people with any type of skin and hair can get them. They’re genetic, so if your parents have freckles, there’s a good chance you will too.

But the sun is the thing that causes them to appear. When we’re exposed to sunlight, a substance called melanin is produced.

Freckles appear when there’s an uneven distribution of that melanin under the skin.

Are they dangerous?

Freckles on their own aren’t dangerous. But if you spend a lot of time in the sun, you should pay attention to any changes in the freckles and get them looked at.

However, pale or fair-skinned people — those who are most likely to have freckles — are more likely to get a sunburn.

Can they be removed?

As people get older, their freckles may fade. But for those who don’t like their freckles, there are slightly uncomfortable laser procedures that can remove them. Others may use creams or makeup to make them less obvious.

However, they can also be fashionable — and you can even find beauty products that will help you to add freckles to your skin.