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. 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.

If you are a parent who is interested in enrolling your twin children in the Washington State Twin Registry, you can complete our enrollment survey online. 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.

Please use this form to request an invitation.