Identical twins, identical classroom: why our boys will study together

It's starting already.
Family members, friends, even strangers in malls and grocery stores.
They mean well.
I really think they do.
But they are ill-informed.
Through no fault of their own.
The lead-in could easily be mistaken for the question.
"Are you planning to send the twins to preschool?" they ask.
Then comes the question, which isn't really a question at all.
"You will separate them, right?"
Followed by the silence when I answer, with confidence.
"No."
But, like I said, the attitude isn't really their fault.
For the past few decades, the prevalent theory among educators has been that all twins fare better when separated in school. It helps them develop individual identities, they say, particularly with identical twins. It gives them more confidence, they argue. It helps them make friends of their own.
But here's the trouble: no evidence exists to support those recommendations, policies or decisions.
Quite the opposite, in fact.
The few studies done on the effects of separating twins in elementary school show that most twins suffer emotionally and socially and that for identical twins, separation can be highly traumatic and might impact academic performance as well.
Consider this finding from a 2004 study conducted by the Institute of Psychiatry at Kings College in London:

"When compared to those not separated, those separated early had significantly more teacher-rated internalizing problems and those separated later showed more internalizing problems and lower reading scores. Monozygotic (MZ) twins showed more problems as a result of separation than dizygotic (DZ) twins."

Or this finding from a 2010 University of Amsterdam study of 839 monozygotic and 1164 dizygotic twin pairs: (This study focused primarily on the effects on academic performance.)

"There is no difference in educational achievement between twins who share a classroom and twins who do not share a classroom during their primary school time. The choice of separation should be made by teachers, parents and their twin children, based on individual characteristics of a twin pair."

The same folks who believe Matthew and Jonathan should each strike out on their own by age 3 wouldn't hesitate to put their own children in classrooms with their best friends. After all, that kind of kinship puts children at ease, makes them less clingy and allows them to be more socially confident.
So why would we separate Matthew or Jonathan from his best friend during this time of stress, excitement and change?
I was relieved today to chat with one of their future preschool teachers, a mother of 17-year-old identical twin boys. She kept her boys together throughout the younger years and, as they got older, took them aside separately to ask whether they wanted to stay together the following year, she said.
Each year, the answer was the same: yes.
As we spoke about our children, children filtered into the classroom where Matthew and Jonathan were playing. Jonathan immediately befriended two boys his age who took an interest in the same tractor that had attracted him. Matthew squatted near a child-sized sofa conversing with a slightly older girl who had sat down with a book.
A barrier of shelves separated Matthew and Jonathan.
Neither panicked at the absence of the other.
Neither looked for the other.
Both put up a good battle when it was time to leave.
And I couldn't help smiling when both boys demanded to know when they could come back.