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The Singular World of Twins and Twin Studies.

Dr. Nancy L. Segal is a Professor of Psychology and Director of the Twin Studies Center, at California State University, Fullerton. See full bio

July 27, 2009

Loss of a Twin

Twin Loss: The Annual Convention

July 15, 2009

Triplets--An Unusual Case

This article is reprinted, in part, from a longer one in a recent issue of the journal Twin Research and Human Genetics. Read More

March 21, 2009

DNA Dilemmas: New Riddles from Twins

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

February 13, 2009

More Octuplets: Combinations and Permutations

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:

February 9, 2009

Why Some Identical Female Twins Are Different

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

February 9, 2009

Octuplets: Views From One Who Studies Two

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

October 22, 2008

Political Pairs

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

July 3, 2008

Twins Reared Apart--But Together Again

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

June 4, 2008

Mistaken Identity—Twins?

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

May 7, 2008

Fraternal Twins--The Hidden Pairs

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

Books by Nancy L. Segal

Entwined Lives: Twins and What They Tell Us About Human Behavior

Indivisible by Two: Lives of Extraordinary Twins

Child Development Basics

The speedy physical and psychological changes that children undergo from birth through adolescence often leave parents wondering how best to care for them at each stage. From how to talk so kids will listen to when to back off and allow them to fail, PT's experts weigh in.

Go to the Child Development Basics page for more on Child Development including:

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Books by Nancy L. Segal

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