They are like any two 11 1/2 year-old-boys. Best friends that aren’t above the occasional fight, the bond that Koen and Tuen share goes deeper than squabbling.
Looking at them, it might surprise you to learn that not only are they brothers— they’re twin brothers.
Dateline has been following their story since they first arrived in 1993.
The two boys are growing up in a world that sees color everywhere, but in a family that says it’s color blind.
Wilma Stuart, mother of twin boys: We are so used to it we don’t see that they are different in color.
Ann Curry, anchor: But you live in a world that does.
Curry: And therein lies the problem.
How they got to this place is its own remarkable story. The Stuarts, Wilma and Willem are Dutch. He’s an engineer, she’s a nurse. Theirs is an extraordinary story that began in the most ordinary way: They married in 1984 and assumed children would follow, but they didn’t. After six years they tried invitro fertilization.
The Stuarts were lucky. On April 2, 1993 Wilma learned she was pregnant, and soon after, they discovered they were having twins— exactly what they had hoped for.
Wilma settled in to enjoy her pregnancy, but the delivery was not as easy. On December 1, 1993, two boys were born by emergency caesarian section. Koen, short for Conrad, arrived at 2:55 a.m.
Wilma: He was beautifully pink. He had blue eyes and dark hair.
The second twin, Tuen, was born just three minutes later. He was not as robust as his brother. He went to an incubator on another floor of the hospital, while Koen was placed in a bassinet at his mother’s side.
It was three days before the Stuarts saw their new babies together.
Wilma: At that time the difference was so big that I immediately said "He is brown, he’s very brown." I knew immediately that something went wrong.
And she started asking questions and looking for an explanation.
Wilma: We would ask nurses, "How come that Koen’s so brown?" They would say that newborn babies have sometimes liver problems, and that they turn yellow. So they would check that in his blood and the level would always be normal and they didn’t talk about it any more, so we didn’t either.
If not the jaundiced condition that so many babies are born with— what was it?
Wilma: I descend from French gypsies and he descends from Mongolian people so a little brown could be somewhere in the family. But it never eased my mind. It never did. He was too different.
With every possible explanation as to why was one of their babies was so dark, there remained the one nagging fear that no one wanted to say out loud.
Wilma: You don’t want to hear someone else say, “Well, we think that’s not your baby. You don’t want to know that.”
Wilma had long ago fallen hopelessly in love with her baby boys, and was haunted by the prospect that one of the boys might not be hers. But not a single doctor had ever raised a question, and in fact many doctors say that it is often impossible to identify the race of a newborn by skin tone. Pigment melanin, which determines skin color, may not fully develop until well after birth.
But what doctors in the Netherlands missed— strangers didn’t.
Wilma: They would say to me, ‘Are these your children?’ and I would say ‘Yes.’ ‘Is this a twin?’ ‘Yes, it’s a twin.’ ‘You must have gotten the scare of your life when he was born.’ And I would say ‘Why? He has two arms, two legs, he has a beautiful face.’
People felt obliged to share their surprise. Whether white or black, people would speak up.
Wilma: We were walking downtown, and there came a black woman looking in our baby carrier, looking at us. And she would say, “Where did you get such a brown baby? How’s that possible?” And we would say “I don’t know. But he’s ours.”
When the twins were six months old, Koen developed a bronchial infection. The Stuarts took both boys to a new pediatrician.
Dr. Brussel: I said, ‘I see two children and one is very white and one is very black. I’m puzzling how that’s possible?’
Wilma: He asked us if it had occurred to us that they were so different in color. And we said, “Yes, of course.”
Dr. Brussel: And when I started the subject she starts crying immediately, Wilma.
Hospital makes a 'regrettable mistake'
After half a year of worrying and wondering, the Stuarts where about to find out if their children, who’d been side by side since life began, were biologically related at all.
Wilma: We didn’t know either what was going on. Was he my child? Was he Willem’s child? Wasn’t he either one of ours?
The possibilities were staggering: Had the lab mixed someone else’s sperm with Wilma’s eggs? Had someone else’s egg been mixed with Willem’s sperm? Or had some other couples fertilized embyro been implanted in Wilma’s womb?
Only DNA testing would answer those questions.
The twins were nearly a year old when the tests came back: The news was at once reassuring and devastating. One of the children Wilma nurtured for nine months in her womb was theirs. But the other was not.
As far as Willem was concerned, Koen was still his child, but as painful as it was, there were some questions that would have to be answered...
Wilma: The immediate next question is what happened? What went wrong? And if Willem is not his biological father, who is?
The Stuarts tried to go on as normal: they marked the boys' first birthday while they worried what would happen if their secret got out.
Living with that fear and paranoia was too much for the Stuarts. They decided to go public on their own terms. They gave one newspaper interview. And on Saturday, June 6, 1995, the paper hit the stands.
Within hours, their story was all over the world. Some of the public response was even stranger than the Stuarts had imagined.
Wilma: When the story came out there were reactions like— “If you’re not happy with your brown child, you can give it to me.” As if we would give away our own child. So amazing.
The hospital called it a “deeply regrettable mistake.” The report of the investigation still has not been made public, but speculation is that a piece of lab equipment called a pipette, like a large eyedropper, had been used twice, causing another man’s sperm to be mixed with Willem’s.
Wilma: They think that that’s what’s happened.
In fact, there were two other couples in the waiting room that day, and one of them was black.
The hospital located the man and confirmed he was Koen's biological father. And though he was under no obligation to meet the son he never knew he had, when Koen was 18 months old, he did.
Wilma: Koen’s biological father just looked at him from a distance. He didn’t try to claim him or take him on his lap or— I don’t think Koen noticed him as being someone special.
Koen had met his biological father but it was up to Stuarts to tackle the question every child asks, “Where did I come from?” For the Stuarts, answering that question proved a lot more complicated.
Wilma: I’ll tell him that the fact that you’re born means that your urge to be born was so big that you couldn’t wait for a black mommy.
Even by the age of two, the boys seemed to have absorbed their differences on some level.
Wilma: When they see babies on television and it’s a white baby, all white babies are named “Tuen.” And when we show them a picture with a darker baby it’s always named “Koen.” It’s adorable.
Whatever their differences, from the beginning the twins undeniably had that special bond of siblings who shared a womb for nine months.
Wilma: Yeah, they can be together in a very small space without getting in each other’s way. For instance, we don’t have a big bathtub and they sit in together. It’s never a problem. It’s duo penotti. That’s a white and brown chocolate cream for on your sandwich. That’s what Koen and Teun are called, duo penotti. Black and white in one body.
From toddlers to 4 years olds
As Wilma and Willem Stuart watched their babies grow from toddlers to rough and tumble 4 year olds, each with his own distinct personality, they never had the luxury of forgetting the extraordinary circumstances of the boys’ birth.
Wilma: It’s something that runs through your mind at least once or twice a day, everyday, every week, always. And they thought it always would.
The toddlers went to a small preschool several days a week, as they played with other kids in their racially mixed neighborhood. The boys were already aware that the first thing adults noticed about them was their different skin colors.
Willem: Sometimes, they make jokes about it then they lay in the sun. Teun wants to get as brown as Koen is. And then after 15 minutes they lay on the back, on the belly, then they hold their hands together. Koen says “I won. I am the brownest.” Then they'll laugh.
Wilma and Willem had been purposefully frank with the boys about their differences and what makes them so special. Wilma said Koen had two daddies because a doctor wasn’t careful.
Wilma: Did he pay enough attention when he made you? “No, he didn’t. He mixed the colors from another daddy and that’s why I am brown, and Teun is white.”
On some level, they understood.
Wilma: How many daddies does Koen have?
Wilma: A white one--
Teun and Koen: And a brown one.
Wilma: When I talk with him about his two daddies, he's always saying “I’ll keep this one, I don’t the other one.” So, cute, yeah. He doesn’t need the other one yet. Maybe later when he is older.
Then like now, the twins attracted looks and often unwanted attention. Koen was particularly aware of it.
Wilma: He walks up to these people saying, you don’t need to stare at me like that. People don’t expect children to be that frank but they are. We teach them to be because they need, they need to be able to defend themselves against this kind of stuff when they are alone later.
Teun and Koen at 8 years old
“Dateline” visited the boys again in 2002 when they were 8 years old. We found Tuen and Koen to be happy, healthy boys who loved tennis, swimming, and wrestling with each other.
It only took a few minutes with the boys to see how close they really were.
Wilma: I think they’re like real siblings. They love and hate. I mean, they fight occasionally and they hug and they take care of each other. And I think they have a pretty normal relationship.
Not only with each other, but with other kids. It’s grownups who had trouble. And they always asked the same questions.
Willem: Are they brothers? And then I can say, yes, they are twin brothers. But always you have to go through the first steps again.
The greater challenge was consoling Koen when people assumed he had been adopted.
Wilma: You see people looking at him as being the strange part of the family. Sometimes, it bothers me. Not everybody has the guts to come up and ask. They’re just staring and wondering and making their own stories. And that’s not nice.
Since the boys so often had to defend the fact that they are twins, the Stuarts thought it might be fun to celebrate being twins.
In 2002 they planned to attend the Twins Day festival in Ohio, an annual event for twins from all around the world. The Stuarts were especially looking forward to the “least alike” competition.
But then a few weeks before the festival the Stuarts were crushed to learn that Koen and Teun would not be allowed to participate because festival organizers concluded they weren’t really twins.
They checked with several doctors, who told them that the Stuart boys were biologically half-brothers. The festival, unfortunately, is for medical biological twins.
Wilma: I was very disappointed. But I was also a bit angry. I told them that you need to ask yourselves, “What makes a twin?” Is it a biological fact? Or is it the fact that you grow in the same womb, being born on the same day, growing up together? I think these things make a twin.
The boys were devastated. The Twins Festival was scratched off the itinerary and the Stuarts went ahead with their trip to America. But Wilma understood that pressures from outside their family had increased— and would only get tougher for her boys as they got older.
Wilma: I think these are the easy times. They’re little. You talk a bit here and there. But when they’re really starting puberty, I think that’s gonna be a very hard time.
Tuen and Koen at 11 and 1/2 years old
And she was right. This summer, we visited the boys again—they’re now 11 and ½ — and discovered that the constant questions they faced about whether they really were twins had begun a painful cycle for the boys, especially for Koen.
Raising their children Koen and Tuen has been a continuing journey. The family has faced a series of ups and downs. But through it all, Wilma and Wilem say the greatest gift has been the incredible friendship their two boys share.
Curry: Well, what’s the best part about being twins?
Tuen: You’re never alone.
It has been three years since we last checked in on the Stuart family.
Curry: Why do you allow us to come into your lives? Why is it that you do this?
Wilma: It’s good for us just to, every now and then, sit down and really talk about this. Because this is not what we do everyday, you know. We have to go to work and school and— so our day to day life is not about this.
Wilma: It’s just about having these two boys grow up and be healthy, be happy.
Taunting by other kids, pulling the racecard on each other
t 11 and a half years of age, Koen and Tuen have hit some bumps in the road and Wilma and Wilem continue to worry, like all parents, that their children will face cruelty and hardship. But unlike all parents, they have additional things to worry about especially when it comes to Koen.
Curry: You are trying to raise him to be strong enough to deal with the future that you can’t protect him from?
Wilma: Yeah, absolutely. Yeah.
Teun and Koen are like any brothers: they love each other but when they fight, they go straight for the jugular.
Curry: So have they ever pulled the race card on each other?
Willem: Oh yes, they have.
Curry: Because they know that’s where it hurts.
Willem: Well, when you want to hit someone, you want to hit them good.
But now that they are older other kids in town, they also know how to hit the boys where it hurts, and it is usually directed at Koen.
Curry: You’re worried about the possibility of racism.
Wilma: Oh yes, absolutely—
Just last summer, Wilma was with Koen when another boy started chanting “Who’s your daddy” at him on the street.
Wilma: I stopped. And I thought, “This is a very important moment.” I was not gonna say anything. He had to do it by his own. And he stopped and he turned at this child. And he said, “I at least have a daddy.” I thought, “Yes. This is it, this is good.” I was very proud of him.
Koen can now stand up for himself, but the last few years have been particularly rough for him and, as always, the curiosity of strangers has been a burden.
Wilma: They’re always wondering whether Koen’s my child.
Curry: And they say this in front of Koen?
Wilma: Oh yeah.
Curry: Is this your son?
Curry: And when you say "Yes," they say—
Wilma: “Are you married to a black man?” “No, I’m not.” He knows where children come from. So he knows what these questions are about.
Koen now understands the implied infidelity in strangers’ questions— years and years of questions.
When was it one question too many? By the time he was 9 or 10 years old, Koen had had enough. He didn’t want to be the source of curiosity anymore. And in the Netherlands which is overwhelmingly white, he just wanted to blend in.
Wilma: He really did not like his curls. And his color, he wanted to be white. I always firmly told him, Koen, this is who you are, this is your color and this is your hair, and we love you very much. This is it, this is you.
Willem: You gotta live with it.
Wilma: Yeah, right. You cannot blow it out of proportion. Because that will make him more and more insecure.
It’s been more than eight years since they’ve had any contact with Koen’s biological father —his desire to be part of Koen’s life was not as great as the Stuarts had hoped. They no longer know where he is.
Wilma: We just wanted to have someone explain to Koen what it means to be black and he needs to know about black people. He has to see them, talk to them, play with them. But we didn’t succeed in that, and that’s bad. You know, we really think that’s bad.
For the Stuarts there was yet another challenge to face. Koen, sick of the unwanted attention, no longer acknowledged to outsiders that he was a twin.
Wilma: Being a twin was not open for debate.
Curry: He would say he was not a twin.
Wilma: He was not. No, he was not a twin.
Wilma: Because the next question would always be, “How is that possible?” I think he did not have words enough yet to explain.
'World's least alike twins'
This year, organizers of the twins festival the Stuarts had been uninvited from four years ago had a change of heart and declared the boys twins after all. The Stuarts decided to go, hoping the trip might help Koen and Tuen rediscover their love of being twins.
Wilma: There was no negativity. There was this woman saying to them, “Gosh you’re a twin. You must be special. You’re cool... you’re cool.’ The reactions they all got were all very positive.
The boys had a blast and the whole family was fixated on the twins’ winning the “least alike competition.”
Wilma: Being chosen there to be "least like" twins was very important to them. They were very afraid that they were not going to win.
They all wondered what the twins who could bump Koen and Teun to second place might look like— and decided they had a pretty good chance. They won the title, of course.
Wilma: They are the world’s most least alike twin.
For the boys, recognition of their status as twins was priceless.
Wilma: It was great. They had a great time. It’s an ultimate acceptance of the world outside that they really are a twin, and not just two boys. I think it’s really important to them.
For the two boys, being celebrated for their differences finally answered all the questioning looks, nasty teasing, and outright expressions of disbelief they've endured all these years. Not only are Koen and Teun twins, they are the world's most least alike twins.
Curry: And what makes you so happy about having—winning the least alike competition?
Tuen: They think we are not real twins—real twins.
Curry: So you proved something.
Koen: Yeah. It felt great.
The medal they received was proudly displayed. Their mother says it has changed the boys’ feelings on being twins—at least as far as the outside world is concerned. At least for now.
Curry: Koen has evolved in his thinking about being a twin.
Wilma: Yeah, absolutely. He has, in that way, grown. He’s able now to explain what happened. And I think he came to terms with that as a fact. And that now he is learning to accept himself and be proud of himself. And yeah, I think, in that way, he has evolved a long way.
Curry: And if anybody ever asks you again are you twins, what do you say, Koen?
Curry: Yes. And what do you say, Tuen?
Tuen: Yes. I say watch NBC.
So, what will happen to Tuen and Koen as they approach their teen years? How will the fact that they're of different races affect them as they begin to date, and look for a job? We'll let you know...we'll be checking in to see how the "ordinary" challenges of growing up are handled by these extrarordinary boys.
© 2013 NBCNews.com Reprints