The Power of Two

Here were two young children with shared DNA being raised apart, a near-perfect nature-versus-nurture experiment. Because twins allow researchers to look at the same or similar DNA in various environments, they are already the source of much of what we know about the role genes play in who we are. But so far the science has been limited by two realities of family life. One: twins are usually raised together in the same environment. Two: in the rare cases where they've been separated, they typically don't find each other until later in life. So any information about their early lives is filtered though the cloudy glass of memory.

But now the two Merediths are giving researchers a chance to study young, separated twins in real time, and therefore, more accurately. Nancy Segal, the director of the Cal State Fullerton Twin Studies Center, has collected 10 sets of twins (five fraternal and five identical sets) adopted from China by different families, including Meredith Ellen and Meredith Grace. Her groundbreaking prospective study (as opposed to a retrospective study) includes a control group of 30 additional sets of Chinese adopted twins (27 of which are identical) being raised together. (Quick biology refresher: Fraternal twins occur when the mother releases two eggs, which are then fertilized by two different sperm cells. Identical twins result from one egg, which, after being fertilized by one sperm, splits. The term "identical twins" is actually outdated because their DNA, once thought to be exactly the same, has been found to have some variations. Monozygotic, meaning "one egg," is now preferred in scientific circles.) Segal is taking a broad look at her subjects, watching the twins' intellectual and personality development, how they've adjusted to adoption, and whether they become more or less alike as they age.

For all the evidence twins can offer about genes and environment, little is known about what goes on between twins themselves. Dr. Thomas Bouchard, a professor of psychology at the University of Minnesota and a former colleague of Segal's, is the godfather of twin research, having run the Minnesota Study of Twins Reared Apart for two decades. More than 130 published papers later, he admits he has no clue what bonds twins together. He remembers watching two 18-year-old male monozygotic twins, who'd been raised by separate families, meeting for the first time. Their connection was so intimate at that very first moment together that they held hands and walked off, talking. "I almost thought it was a miracle," Bouchard says. "I'm not a religious person. It's just a profound sort of thing. "

While it's still early in Segal's research, the initial wave of data regarding the first time the separated twins in the study met is already shedding some light on the twin relationship. Meredith Grace was introduced to her sister in the parking lot of a Birmingham hotel. Both girls had been told only that they were from the same orphanage. Days before, the 4-year-olds had spoken on the phone. Before hanging up, Meredith Grace whispered "love you" to the sister she'd never met. And now here she was. Across from Meredith Grace was the same glossy black hair and khaki skin color she'd seen before in the mirror, but never recognized in her own family. The girls circled each other for just a moment. When they finally released each other from that first hug, they took each other's hand, Meredith Grace on the left, Meredith Ellen on the right. Meredith Ellen told Meredith Grace, "I think we were born together."