Participating in studies

What types of studies does the Twin Registry conduct or facilitate?

Most studies conducted directly by the Twin Registry involve collecting health data. Studying the health of both identical and fraternal twin pairs gives researchers the opportunity to better understand genetic and environmental influences on health and illness. Some studies involve in-person visits, which may include procedures such as blood draws, urine collection, cheek cell collection, saliva collection, MRI scans, surveys on paper or computer, physical exams, sensitivity testing, exercise, and other tests. We also occasionally conduct studies through the mail that may involve surveys or collection of biological samples such as urine, cheek cells, or saliva.

We may also work with other research groups or universities outside of the Twin Registry. If we are asked to provide twin pairs for such outside studies, we would first contact you to give you details about the studies and ask your permission to give your contact information to those researchers. We will never share your information with anyone outside of the Twin Registry without your directly expressed permission.

Participating in any study or giving us permission to pass along your information to outside researchers is always completely voluntary. You may decline to participate in these studies at any time.

What safeguards protect Twin Registry members who participate in research studies?

The Washington State Twin Registry takes many precautions to protect the rights of its members.

Federal regulations require that all research conducted by federally funded institutions must be overseen by an independent ethical review committee called an Institutional Review Board (IRB). The Twin Registry works closely with our IRB committee to review each study to make sure that:

  • The rights of participants are protected.
  • Participants are not subject to unreasonable harm (physical and/or emotional).
  • Information about participants is kept confidential.

Before any research project begins recruiting participants, the researchers submit their study protocol for review by the IRB. The IRB looks closely at how participants will be recruited, what tests or procedures the participants will be asked to do, and how the participant’s data will be used. After the research has begun, researchers must submit regular progress reports to the IRB, as well as reports of any problems that occurred that might potentially harm the participants.

Consent forms, which must be approved by the IRB, are a very important safeguard for research participants. The consent form describes the study in detail, including why the research is being conducted, what procedures you would be asked to do, what the potential risks or side-effects are, where and how your data is stored, and how you can withdraw from the study at any time. During a process known as informed consent, the researcher reviews the study consent form with you and answers any questions you may have about the study before you decide whether to participate in the study.

It’s important to know that your participation in any research study is voluntary, and that as a research participant you have the right to:

  • Know why the research is being done
  • Know what you will be asked to do
  • Know the risks, side effects, or pain that may occur
  • Know what good may come from the study
  • Know how your private information will be kept safe
  • Know whom to contact with questions or concerns
  • Ask questions at any time
  • Decide to participate without being pressured
  • Drop out at any time without penalty
  • Keep a copy of the consent form you signed

The Washington State Twin Registry has been reviewed and approved for human subject participation by the Washington State University Institutional Review Board.

The Twin Registry takes our responsibility to conduct safe, ethical, and high quality research very seriously. If you have questions about your rights as a Twin Registry member, please email us at or call 1.833.432.8720.

Will I receive results from the study I participated in?

When the data that is collected from a study is analyzed, it is studied in a general way, e.g. identical twins experience similar levels of pain compared to fraternal twins. Typically it is results from the group that are significant, while individual results are not meaningful. These findings are usually published in peer-reviewed journal articles, which are available to all.

The results that you receive from a study will vary depending on the type of study. Results may be as simple as the vitals that we collect during the visit, or more detailed such as providing a printout of collected data when the study is completed. This information would not be published in a journal, but participants may find it interesting to see what kind of data is collected in our study.

Individuals participating in the AIR study will receive a summary of their activity
Individuals participating in the AIR study will receive a summary of their activity


Will my twin and I get to learn if we are identical or fraternal?

Some studies collect biological samples (blood or saliva) that can be processed for DNA. Zygosity testing (laboratory testing to determine whether you are identical or fraternal twins) can be done on your DNA samples. However, most Twin Registry studies do NOT perform zygosity testing on DNA samples.

If a study tests your zygosity and that information becomes available to the Twin Registry, you and your twin will be sent a letter and a release form giving us permission to release your results. We will only send this information once both you and your twin have signed the release.

For more information on zygosity, click here.