GRAND HAVEN, Mich--Doctors say the chance you give birth to twins with different skin tones is one in a million.

Although uncommon, there's a pair growing up in Grand Haven.

Briana Laws says it took her about two weeks to notice that her fraternal twins, Aila and Adalynn, were different skin tones... one black, the other, white.

She tells FOX 17, at one point, she wondered if her babies were switched at birth.

All jokes aside, she says she couldn't be more thrilled to have these two little girls.

"They’re good babies, it’s just difficult when you have two," Laws said.

Two babies who have completely different traits.

"Aila is more quiet, she’s a lot more calm and she babbles more and she’s a little more clingy," Laws said. "Adalynn has a temper, very boisterous."

"It’s kind of a big deal. I guess it’s a good way to be able to tell them apart," said Laws.

One has blue eyes and curly hair, the other has straight hair and brown eyes, but the biggest difference is their skin.

"They’re gems, they’re one in a million, it’s a special thing," Laws said.

According to geneticist, Helga Toriello from Spectrum Health, although it's rare, it's happened before.

"It basically comes down to chance," Toriello said.

According to Toriello, it occurs when one parent is multi-racial and the other is white.

In this case, Briana tells us she's a quarter black and her husband, Cameron, is 100 percent white.

"The average situation we would see a child have a skin color in between that of both parents," Toriello said.

But with these twins, that's not the case. It's a rarity, Toriello says comes down to the genes each baby gets.

"If a child gets some genes that code for a lot of pigment from one parent and some genes that code for less pigment from the other parent, you’ll expect to see an average," Toriello said, adding that once those genes start to mix, things change.

"Such as one child receives almost all of the genes that code for pigment from the one parent and then the genes that code for very little pigment from that parent," she said.

Two children at two ends of the spectrum. Both of them at the center of these parent's lives.

"Nobody will ever know they’re twins," Cameron Laws said. "You love them all the same."

Although the two girls do have different skin tones, we're told their 2-year-old sister still struggles telling them apart. She calls both of them the same name.

There's also a pair of twins from the UK who were born with different skin colors and traits. Their picture is below.