"We're
not just talking about a pair of genes leading to two individuals
looking alike. We're looking at many many genes that operate to
give them these (identical) features. If they were fraternal twins,
you might put a reasonable probability on how that might happen.
But if we're talking about different lineages, geez, the chances
would be ridiculously small."
That's
because having identical features requires both girls to share a
large number of identical genes. Currently biologists estimate that
there are 35,000 to 80,000 genes in the human body. And each of
those genes comes in several variations, or alleles. For the Hansen
girls to fool the human eye, a significant portion of Brooke's alleles
and Bree's alleles would have to match up.
"There
are literally billions of combinations that go to make up any individual
human being - thousands of combinations of alleles go to make up
the face alone," said Professor Duane Jeffery, who teaches
genetics at Brigham Young University. "We're talking about
thousands of matches here. The chance of that happening I can't
even begin to calculate."
It's
stiff odds like that that have convinced Kris and Shelly Hansen
the likeness between their adopted and natural children is no genetic
coincidence. The Hansens are devout members of the Church of Jesus
Christ of Latter-day Saints. They say the affinity between their
daughters is a sign, an indication Brooke's adoption was of divine
inspiration.
"I
think the Heavenly Father wanted Brooke to be in our family,"
said Kris Hansen, the girls' father. "Brooke was the answer
to all of our years of prayers."
"Counterfeit
Twins"
The
Hansen's understanding of their daughters' improbable resemblance
is founded on that belief - that Brooke was a divine answer to seven
long years of infertility. They see heavenly guidance in the way
their lives crossed paths with hers: Moving from California to Layton,
Kris and Shelly felt an inexplicable tug toward a run-down apartment
in Bountiful. They abandoned a deposit on an upscale flat in Layton
and moved into the Bountiful complex, where they met the man who
would connect them to Brooke's birthmother.
Shelly
got pregnant and gave birth to Bree shortly thereafter. At 90 days,
when Bree's face began to mirror her sister's, it only confirmed
the Hansens' sense Brooke's adoption was part of a larger plan.
"There
are no bloodlines, yet they're the same height, the same shoe size
- they do everything alike," Shelly said. "It's a magical
thing. To me it means they were supposed to come together."
On
their cul de sac in Foster Hills, where the girls skip rope and
chase frogs, their likeness has earned them the nickname "the
Counterfeit Twins." Rightly so: Almost everyone on the block
has been fooled by their resemblance.
That
group include Phil Mackert. Mackert has lived next-door to the Hansens
for more than a year. In that time he has seen the girls on numerous
occasions, including weekly get-togethers with the Hansens and other
neighbors. Still Mackert believed Brooke and Bree Hansen were multiples,
until just recently, when he was set straight.
"I
had no idea one of them was adopted until last weekend," Mackert
said. "They look like they're from the same gene pool. I thought
they were twins."
Mackert
isn't the only one. In primary education at Foster Hills 1st Ward,
the Brooke and Bree mix-up is cause for weekly confusion.
"We
do singing, and they'll say Brooke or Bree. Whoever they call, one
of us will just go up," said Bree. "They don't even know
which one's what yet. They'll point to me and call Brooke. And then
she goes up and they'll say, 'No, no, I wanted her.'"
Parks,
markets and malls are breeding grounds for similar confusion.
"We
have people stop us in the store and say, 'How do you tell them
apart?' And: 'Isn't it fun to have identical twins?'" said
Shelly Hansen, the girls' mother. "I say they're not identical
twins and, well, they're not even twins. But people just look at
me like, 'What?'"
"Kids
their age especially - they don't understand it. So it's easier
to just say, 'Yeah, they're twins.'"
Scientific,
Religious Explanations
When
scientists confront cases as improbable as the Hansen's, their first
course of action is to search for mitigating factors, factors that
might help explain why the case appears more improbable than it
is.
Professor
Jeffery notes that Brooke and Bree grew up eating the same food.
Nutrition is known to effect bone growth; identical nutrition levels
may help explain why the girls' facial structure is so similar.
Jeffery also points out that Brooke's having light skin and African
heritage is not a complete mystery either: 32 to 33 percent of genes
found in today's African-American population comes from Caucasians,
a remnant of antebellum sexual practices.
There's
also the matter of dressing both girls alike, a practice Professor
Schwaner says can make people who aren't identical look so.
In
the years she has spent raising the counterfeit twins, Shelly Hansen
says she has considered such nurture-over-nature arguments and finds
they have merit. But do they explain everything? "Definitely
not," she said. She maintains a heavenly influence is at play
in the girls' matching identities.
Not
everyone in Utah's scientific community dismisses that possibility.
Cheryl
Whitelaw, professor of statistics at Southern Utah University, says
she often sees divine influence working through science, nudging
numbers and guiding events that would otherwise be highly unlikely.
In the Hansen case specifically, Whitelaw says the probability of
the girls ending up identical is small enough before considering
the probability of them ending up in the same home, as sisters.
"You
think of all the children being adopted and all the families that
want to adopt a child - it becomes a numeric permutation with a
very very small probability," Whitelaw said. "That's where
a little bit of our Heavenly Father's hand comes in here. Maybe
God had that child look a lot like their own to let them know she
was sent specially to them."
Others
familiar with the case stress there are alternative explanations
within the framework of science. For one, Jeffery says, the Hansens
highlight all that biologists have yet to learn about genetics.
He suggests that in future, when more is known about how genes play
out, the case of the Hansens might be much more explainable. Until
that time, the professor urges people never to discount the power
of chance.
"The
improbable does happen," he said. "This is highly unlikely,
but so is winning the Lotto. People do win the Lotto. The odds have
to happen somewhere."
In
happening to the Hansens, Jeffery said, the girls are very lucky.
That's precisely how Brooke and Bree feel.
"I
know they feel very fortunate to have each other," Shelly said.
"Earlier Brooke told me, 'Mom, I don't think I'm adopted. I
just think I'm a twin.'"
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