Joining the Washington State Twin Registry

The Washington State Twin Registry is a database of twins and their family members who are interested in participating in research on health and behavior.

Twins can make an important contribution to research. You are eligible to participate in the Washington State Twin Registry if both you and your co-twin agree to participate. 

If you are eligible, you and your co-twin will be asked to complete a brief questionnaire. You may be contacted to take part in specific studies. Participation in these studies is voluntary. Periodically, registry members and their family members may be invited to participate in new studies developed by scientists throughout the world.

In any study, participation is completely voluntary and you or the twins may withdraw from participation at any time. Some of our studies involve in-person visits while others are conducted through the mail, which allows us to include twins no matter where they live.

Unfortunately, we are not able to enroll triplets, higher order multiple births such as quadruplets or quintuplets, or individuals who do not have a living twin. Once we have received a completed survey, you will be enrolled in the Twin Registry.