fAbout Us

The Minnesota Center for Twin and Family Research (MCTFR) seeks to identify genetic and environmental influences on development and psychological traits. The MCTFR is based in the Psychology Department within the College of Liberal Arts at the University of Minnesota, and is one of the largest research centers of its kind in the United States.  It is composed of many projects, including the Minnesota Twin Family Study (MTFS) and The Sibling Interaction and Behavior Study (SIBS).  Participants in the MTFS include families with same-sex identical or fraternal twins who were born in Minnesota. The SIBS study is comprised of adoptive and biological siblings and their parents.  Most participants partake in day-long visits to the MCTFR, and due to the longitudinal nature of our projects, they return every 3-4 years for follow-up visits.  We are not currently recruiting any new participants.   

The MCTFR is a team of more than sixty people which operates by means of a committee structure.   To find out more about the MCTFR staff and collaborators, visit our Staff page.  Our research is funded by grants from the National Institutes of Health (NIH).  For more information on the confidentiality protections for research participants, visit the NIH website.   Research that has come from our work can be found on NIH’s online open access database, PubMed Central (PMC).
On this Page:
Our History

Our History: A Timeline
  • Male Project, est. 1987: The inaugural study at the MCTFR, which includes male identical or fraternal twins who were born in Minnesota. A second cohort began in 2000.
  • Female Project, est. 1992: The second study at the MCTFR,which includes female identical or fraternal twins who were born in Minnesota. A second cohort began in 2000.
  • SIBS Project, est. 2002: Comprised of adoptive and biological siblings and their parents.
  • GEDI Project, est. 2007: A project that has added the study of DNA to MCTFR research.
  • MRI Imaging Project, est. 2007: A project that has added the study of Magnetic Resonance Imagine (MRI) to MCTFR research


Newsletter Archive

Below is an archive of our most recent newsletters. They include articles on our newest projects, features on our staff members and their work, and fun games and facts. Enjoy!




November 29, 2021
HBCD Study featured on ABC News
U of M team leading 'largest study of early childhood brain development'
(click to view video)
“This is an incredible opportunity. It will certainly be the largest study of early childhood brain development that has yet been conducted in the United States or the world to my knowledge.” -Dr. Sylia Wilson

January 31, 2018
ABCD Study featured on the Today Show (NBC)
New study looks at how teen brains function (click to view video)
"The federal government has launched the biggest study ever of teenagers' brains, looking at everything from homework to screen time. As our Brain Power TODAY series continues, NBC special anchor Maria Shriver reports."


FreakonomicsJune 3, 2011
The Church of Scionology

MCTFR Principal Investigator Matt McGue is interviewed by Stephen Dubner of the Freakonomics radio program on the topic of heritibility, which "seeks to estimate is the percentage of individual differences in a trait that can be attributed to inherited genetic factors."

PDF: Excerpt of the Interview with McGue
Website: Full Transcript

March 31, 2011
FOX 9 News:
Researcher Decodes Viral Twin Talk Video

A viral video showing infant twins that appear to be having an entire conversation has people talking about what the pair is actually doing. FOX 9 News spoke with Kevin Haroian, from Minnesota’s Center for Twin and Family Research, to get the scoop. The original YouTube video can be found here.



February 3, 2011
University News Service:
MCTFR wins Second Place at 2011 Quality Fair

The concept presented on the MCTFR poster was entitled Principal Investigator Dashboards. It introduces an auto-updating application that helps PIs keep track of resources and progress throughout the Center. For more information on the 2011 Quality Fair: 42 Posters each Tell a Story of U of M Improvement Projects









January 28, 2011
MPR News: Studying Marriage: What Women Want and How Men Behave
MCTFR collaborator Dr. Alexandra Burt from the Michigan State University Twin Registry talks about her research on marriage and behavior.

Audio | Webpage

Fall 2010
University News Service:
MCTFR Principal Investigator Bill Iacono honored with Regents Professorship, the highest honor at the University of Minnesota.
Iacono Regents

Photograph by: Patrick O'Leary






Groups & Services
Adoptees Have Answers - Adoptee-focused connections and resources
DNA Interactive - All about DNA
Environmental Impact and Epigenetics - Explaining differences between identical twins (University of Utah)
Facts about Multiples - All about multiples
Mothers of Super Twins (MOST)
Multiple Connections
of Minnesota (formerly Twin Topics)
National Organization of Mothers of Twins Clubs, Inc.

Population, Policy & Aging Research Center
Duke University
St. Paul Mothers of Multiples (MOM) Support and Education for Mothers of Multiple Birth Children
Twin Services Consulting
Twinless Twin Support Group International
Twins List Resources and Information
Twins World

Twin Zygosity & Paternity Testing
DNA Diagnostics Center (DDC):

  • Life Sciences Building, Suite 1114, 700 South 10th Avenue, Minneapolis, MN 55415
  • 1-800-613-5768 (this is the national line)
  • There are a few different versions of the paternity test (which you can use to determine zygosity of twins) including Legal testing and Home testing.  They are the same test, but the Legal test needs to be administered in a lab or hospital. 

Other Twin Research
Australian Twin Registry
Colorado Longitudinal Twin Study
Colorado Twin Registry
King's College Department of Twin Research & Genetic Epidemiology
Michigan State University Twin Registry
Mid Atlantic Twin Registry
Minnesota Twin Family Study (MTFS) on Wikipedia
National Twin Registry
Twin Research Registry at SRI International
Twins Study @ Harvard

Books, Magazines, & Films


Twin researcher Dr. Nancy Segal's book Twin Mythconceptions came out in April 2017.

False Beliefs, Fables, and Facts about Twins sheds new light on over 70 commonly held ideas and beliefs about the origins and development of identical and fraternal twins. Using the latest scientific findings from psychology, psychiatry, biology, and education, the book separates fact from fiction. Each idea about twins is described, followed by both a short answer about the truth, and then a longer, more detailed explanation. Coverage includes embryology of twins, twin types, intellectual growth, personality traits, sexual orientation of twins, marital relationships, epigenetic analyses, and more.


PBS Film: The Secret Life of Twins
Aired: April 2017
Identical twins are fascinating. Born with the same DNA, they go on to develop both astounding similarities and staggering differences. This groundbreaking film meets some of these amazing human pairs. Discover how twins can be identical but grow up to become very different people. These remarkable stories shed light not only on what it means to be a twin, but also on what it means to be human.

art The Art of Parenting Twins
by Adam P. Matheny, Jr., Ph.D., Professor of Pediatrics, University of Louisville
"Written with clarity, intelligence, and accuracy, this handy book is a 'must have' for parents of twins and other multiples, [for] multiples themselves and professionals or organizations concerned with guidance and counseling. One could not ask for a more resourceful book."

The Same but Different: How Twins Can Live, Love and Learn to Be Individuals
by Joan Friedman, Ph.D., an identical twin, a psychotherapist, and a mother of five including fraternal twins.
"Written to help twins, their families, and significant others interested in understanding more about the intricacies of adult twin relationships."


Twin researcher Dr. Nancy Segal's book Born Together - Reared Apart: The Landmark Minnesota Twin Study came out in June 2012. Dr. Segal also has three other books, including Someone Else's Twin which tells the story of two twins separated at birth because of an accidental switch with a non-twin infant at the hospital. It was published in August 2011. On Dr. Segal's website and blog, you can find links to her other books, Somone Else's Twin, Indivisible by Two and Entwined Lives, as well as other articles on twins and twin issues.

Emotionally Emotionally Healthy Twins: A New Philosophy for Parenting Two Unique Children
by Joan Friedman, Ph.D., an identical twin, a psychotherapist, and a mother of five including fraternal twins.
Dr. Joan A. Friedman outlines the seven key concepts for helping twins develop into self‐realized, unique individuals and offers parents specific strategies for each stage in their children's growth, from infancy to adulthood. The book helps parents understand each twin's emotional needs. *This is a great books for twins to read, as well as their parents.

TWINS Magazine - the magazine for multiples since 1984!

Article: What is a Twin Registry

TWINS Magazine Message Board - an online discussion site

video Video on Twin Identity (2008): Twin expert Joan Friedman, Ph.D. shares advice on The Rachel Ray Show with a twin who wants to be seen as aunique individual.
Adopt Growing Up Adopted : A Portrait of Adolescents & Their Families by Peter Benson, Ph.D., Eugene Roehlkepartain, and MCTFR collaborator Anu Sharma, Ph.D. Available for checkout through most libraries and through WorldCat. It includes information on identity, attachment, family realities and dynamics, mental health, transracial adoption, and implications for families, services and public education.
Ghost A Ghost at Heart's Edge: Stories and Poems of Adoption, Edited by Susan Ito and Tina Cervin. Contributers include Isabel
Allende and Joni Mitchell. "Fifty short stories and poems...Written from the point of view of birth parents, adoptive parents, and adoptees, this unique anthology spans nations and cultures."
Lucky Lucky Girl, by Mei-Ling Hopgood. An autobiography of a woman who was adopted from Taiwan when she was seven months old by a family in Michigan, and who was reunited with her birth family in her twenties.

Adoptive Families magazine: Leading adoption information source for families before, during, and after adoption




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The U of MN is an equal opportunity educator and employer. This page last updated: November 29, 2021 2:43 PM