The Power of Two

Most of the twins in Segal's study who were older than 18 months when they were reunited experienced a similar instantaneous attraction when they met for the first time, their parents said. A couple of parents used the word "magnetic" to describe the children's overpowering pull toward one another. Others used phrases like "connected at the hip," "totally focused on each other," and "understood everything the other one said." Little 22-month-old monozygotic twins who'd never interacted much with their peers went off to sit at their own table to talk, feed each other, and discuss how "yummy" everything was. Segal believes that the twins' apparent immediate and profound connection comes in part from their shared DNA. "They perceive similarities and it draws them together, like with most people," she says. We already know that spouses tend to have similar intelligence, values, even height. Segal's research shows that even at a very early age people are attracted to people like themselves, and that DNA likely plays a part. "It's another piece to the puzzle of who we connect to and why," she says.

The corollary to the Merediths' elation at finding each other is the devastation at having to separate again after visits. Grief unspools into tantrums. "Worse than I've ever seen before in her whole life," Jim Rittenhouse wrote in his online journal after the girls' first reunion. "One night last week, she got to the point of taking an ice cream whatzit and throwing it with as much force as she could at the table." Since that first meeting almost six years ago-the girls are now 10-they've seen each other about a dozen times. In between visits, they don't speak on the phone because it makes them too sad. But Meredith Grace has told her parents that she thinks about Sissy, as they call each other, 10 times a day. Visits are arranged out of necessity, when the yearning becomes too much. Their mothers start seeing it at the same time. Meredith Grace's attitude flares. Meredith Ellen will cry at night, saying, "I miss Sissy." Sometimes she just starts wearing glasses, which she doesn't need; her twin does. So the word goes out. "Mer is missing Sissy a lot right now. She has even thought tonight that she wishes they could both be back in China together," went one email from Leigh Anne to her counterpart in Chicago. Travel Web sites are checked for sales. Dates are put on the calendar. And the emotion immediately rights itself.