The story of Lucy and Maria Aylmer, 18-year-olds whose father identifies as white and whose mother is "half-Jamaican" (and, we're to assume, thinks of herself as black), is just the most recent one about fraternal twins born with such dramatic variations in complexion that they're seen by many — and even see themselves — as members of two different racial groups.

Now a host of morning news program is being accused of making racist remarks after appearing to congratulate Lucy on turning out lighter than her sister, according to this video snagged by the Daily Mail.

"'Maria has taken after her half-Jamaican mum with dark skin and brown eyes and curly dark hair, but Lucy got her dad's fair skin, good on her, along with straight red hair and blue eyes," Samantha Armytage of Australia's Seven network said, introducing the segment on the twins.

In the video above, you can see co-host David "Kochie" Koch looking taken aback at what appeared to be a statement shamelessly celebrating light skin over dark. Many viewers agreed — there's even a petition asking Armytage to apologize for the comment and its implications.

But a Seven spokesperson told the Sydney Morning-Herald that the remark was just part of a long-running joke, explaining that Armytage often takes digs at herself for the "fair skin that runs in her family."

What "black and white twins" can teach us about race: it's not real

It's obvious that Armytage's "good on her" remark was misguided. Whatever she may have meant, it was widely heard as a celebration of whiteness over blackness — something that's not a joking matter when nonwhite people in Australia and around the world still bear the sometimes deadly burden of racism.

The most fascinating thing about these twins isn't the host's commentary — it's the reminder they offer of how fluid and subjective the racial categories we're all familiar with are.

Lucy and Maria's story, like all the other sensational tales in the "Black and White Twins: born a minute apart" vein, is actually just an overblown report on siblings who, because of normal genetic variations that show up in more striking ways in their cases, have different complexions.

But these stories are fascinating because they highlight just how flimsy and open to interpretation the racial categories we use in the US and around the world are.

They highlight just how flimsy and open to interpretation the racial categories we use in the US and around the world are

Even the Post's description of the Aylmer twins is clumsy, asserting that they're each "biracial" but stating in the very same sentence that one is white and the other is black.

And the fact that the two, despite having the same parents, see themselves as belonging to two different racial groups

("I am white and Maria is black," Lucy told the Post) proves there's a lot more than biology or heritage informing racial identity.

It's a reminder that the racial categories we use are fickle, flexible, and open to interpretation, and have just as many exceptions as they do rules when it comes to their criteria for membership. That's why they have been described as "not real," meaning:

They're not based on facts that people can even begin to agree on. (If we can't even get a consensus that people with the same parents are the same race, where does that leave us?)

They're not permanent. (If Lucy decides one day, like many other people with similar backgrounds, that her Jamaican mother is black and therefore so is she, who's to stop her?)

They're not scientific. (There's no blood test or medical assessment that will provide a "white" result for Lucy and a "black" one for Maria.)

They're not consistent. (Other twins with the same respective looks and identical parentage as these twins might both choose to call themselves black or biracial.)

For more on this, read 11 ways race isn't real, and watch this short video.

"Not real" doesn't mean not important

Of course, none of this changes the fact that the concept of race is hugely important in our lives, in the United States, in the UK where the twins live, and around the world.

There's no question that the way people categorize Lucy and Maria, and the way they think of themselves, will affect their lives.

That's because even though race is highly subjective, racism and discrimination based on what people believe about race are very real. The racial categories to which we're assigned, based on how we look to others or how we identify, can determine real-life experiences, inspire hate, drive political outcomes, and make the difference between life and death.

But it's still important to remember that these consequences are a result of human-created racial categories that are based on shaky reasoning and shady motivations. This makes the borders of the various groups impossible to pin down — as the "black and white" twins demonstrate — and renders modern debates about how particular people should identify futile.

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