Twin Research Registry at SRI International | SRI International

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Twin Research Registry at SRI International

Twins hold a special place in science as a source of insight into human behavior and genetic links. SRI established the Registry as part of its research and efforts to discover more about human behavior. Fraternal and identical twins and multiples of all ages are invited to join the Registry for consideration for research studies.

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Registry members participate in studies focusing on the pharmacokinetics of nicotine, metabolism of commonly used medications, genetic susceptibility to cancer-causing chemicals, and sleep patterns in young twins.

Past Studies

  • Identical and fraternal twins participated in a study to better understand the genetic components of the body’s immune response to the flu vaccine. Read an SFGate article about results from this important study.
  • A total of 1,285 adult twins (including 438 pairs) completed an online survey about various aspects of health and immunity
  • Twins who had been exposed to second-hand smoke (in utero or otherwise) were assessed at the Sean N. Parker Center for Allergy and Asthma Research clinic at El Camino Hospital to better understand the various ways the immune system responds to exposure to tobacco smoke 
  • Twins were included in a Stanford-University led study aimed to determine which aspects of the immune response to the shingles vaccine are influenced by genetics Read more on
  • In partnership with Stanford University, we examined the genetic and familial aspects of pain sensitivity
  • Examination of the renal clearance of the commonly used prescription medication metformin (used in treatment of diabetes) in identical and fraternal twins to determine the role of heredity
  • Comparison of the pharmacokinetics of the medication digoxin (a heart regulator) in identical and fraternal twins to determine whether inter-individual variability is due to genetic factors
  • Examination of the extent to which genetics and environment affect sleep in children
  • Investigation of the role of genetics in response to cancer-causing agents
  • Investigation of whether the predisposition for cigarette smoking is related to how fast the body eliminates nicotine
  • Testing of a biometric recognition technique to capture three-dimensional facial images in identical twins


Read about the twin community in our Twin Stories , and Newsletters, and visit our Facebook page.

More Information

For more information on twins research and twin registries, watch these presentations by TRR Founder Dr. Gary Swan:

  • Twins: Unlocking the Secrets of Nature-Nurture Interactions Part 1 Part 2