Child Development

Twofold

Nancy L. Segal, Ph.D.

The Singular World of Twins and Twin Studies.

By Dr. Nancy L. Segal

DNA Dilemmas: New Riddles from Twins

By Nancy L. Segal on March 21, 2009 - 4:01pm in Twofold

Identical twins’ shared DNA has led to some extraordinary dilemmas when it comes to assigning paternity or assigning blame.  For example, I am aware of several cases in which women have had sexual relations with both members of an identical males twin pair, such that the biological father of their children cannot be identified.  Strangely, the identity of the child’s maternal grandmother (the t Read More

More Octuplets: Combinations and Permutations

By Nancy L. Segal on February 13, 2009 - 11:13am in Twofold

Multiple births are a great addition to research addressing genetic and environmental influences on behavior. It occurred to me that the new octuplets offer some amazing possibilities: The eight babies include:

  Read More

Why Some Identical Female Twins Are Different

By Nancy L. Segal on February 9, 2009 - 2:38pm in Twofold

Behavioral and physical differences between identical twins are fascinating because they are unexpected. Many people assume that when identical twins differ they do so because they are treated differently by others, or because they try to differentiate from one another in order to carve out a separate identity. Read More

Octuplets: Views From One Who Studies Two

By Nancy L. Segal on February 9, 2009 - 2:38pm in Twofold

The recent birth of the Suleman octuplets in southern California has attracted unprecedented attention from physicians, parents and publishers around the world. It is a frequent topic of conversation in coffee shops and classrooms. Issues surrounding the octuplets' child care, health expenses, biological origin and future development-all important and timely--have been debated endlessly. Read More

Political Pairs

By Nancy L. Segal on October 22, 2008 - 1:24pm in Twofold

It's the new hot topic in psychological twin research-to what extent do genes affect our interest and participation in politics? Read More

Twins Reared Apart--But Together Again

By Nancy L. Segal on July 3, 2008 - 11:46am in Twofold

I have always believed that twins belong together, and still do. Twins meeting for the first time as adults describe anger, resentment and sadness at having been raised apart, often for the convenience of others. Read More

Mistaken Identity—Twins?

By Nancy L. Segal on June 4, 2008 - 3:57pm in Twofold

Cases of mistaken identity often reveal an unknown twin. Read More

Fraternal Twins--The Hidden Pairs

By Nancy L. Segal on May 7, 2008 - 3:55pm in Twofold

Fraternal twins are there--but you may not see them. Read More

Quadruplet Varieties

By Nancy L. Segal on April 24, 2008 - 1:03pm in Twofold

Quads come in all shapes and sizes Read More

Unusual Twins and Sibs—Who Are They?

By Nancy L. Segal on April 16, 2008 - 3:50pm in Twofold

Unusual sibships emerge in families with twins! Read More

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