Registry FAQs

The Washington State Department of Licensing (DOL) is unique in that it encodes your last name, first and middle initial, and date of birth in your driver’s license or identification card number. Based on this formula, twins have the potential to generate the same license number. The DOL asks individuals if they are a twin to avoid issuing a duplicate driver’s license number.

We are only able to enroll you into the Washington State Twin Registry if both you and your twin agree to participate. In order to complete your enrollment in the Registry, we need to send your twin an invitation packet as well. With your twin’s permission, please include their name and mailing address on your own enrollment survey. If you prefer, you can give us this information by sending an email to ws.twinregistry@wsu.edu or call 833-432-8720.

If you or your twin have decided not to join the Twin Registry, please let us know. We will remove you from our mailing list and will not contact you again. However, if you and your twin wish to enroll in the future, please feel free to contact us anytime.

We receive routine updates from the Washington State Department of Licensing (DOL) informing us of twins who have recently applied for or renewed their driver’s license or state ID card, after which we send invitations to join. If your twin has not recently provided this information to the DOL, we did not receive your twin’s information. As such, we ask all potential participants to provide their twin’s information.

Yes! We encourage fraternal twins to join the Twin Registry. It doesn’t matter if you and your twin are the same sex or different sexes.

Currently, we are only able to enroll you in the Twin Registry only if both you and your twin are willing and available to enroll. Some studies may permit only a single twin to participate, but Registry enrollment is available only to twin pairs.

Please let us know if you or your twin is not available or not interested in joining, so that we can remove you from our mailing list. You may contact us by email at ws.twinregistry@wsu.edu, or call toll-free at 833-432-8720.

It is possible to join the registry if you are not in touch with your twin. In this situation, indicate that you are not in contact with your twin on the enrollment survey. We will place your enrollment on hold; if we receive your twin’s information through alternative means, we can then enroll both twins in the registry. Providing your mother’s maiden name is helpful in matching you and your twin in our database. We will never share your information with anyone outside of the Twin Registry, including family members.

Yes, twins may participate in studies no matter where they live. Some of our studies involve in-person visits, while others are conducted by telephone or mail. Some studies may provide additional compensation for travel time and costs, but details vary and are provided with the invitation to participate.

We are currently unable to enroll triplets or higher-order multiples in the Twin Registry.

We accept twins of all ages.

Enroll your twin children here. For twins 12 and younger, parents complete the questionnaire for both twins. For twins 13-17, twins complete the questionnaire themselves with parental permission. On the twins’ 18^th birthday, we will send them an invitation to continue their participation in the Registry as adult members.

No. the information you provide to us through the enrollment survey is completely voluntary.

We will ask for your social security number, but providing this information is optional. Your social security number can be useful in finding you if you move or lose contact with us. If you provide it, your social security number will be kept separately from the rest of your information to minimize the possibility of identity theft.

We will ask for your mother’s maiden name, but providing this information is optional. Your mother’s maiden name will be used as an extra way to verify that you and your sibling are twins.

All paper forms with personal information that you give to the Twin Registry are kept in locked cabinets in a locked office within a secured building. All digital records with personal information are kept in password-protected computer files on an internally secured server.

Your mother’s maiden name will be used as an extra way to verify that you and your sibling are twins, but providing this information is optional.

All paper forms with this and other personal information are kept in locked cabinets in a locked office within a secured building. All digital records with this and other personal information are kept confidential.

We will ask for your social security number on the enrollment survey. However, it is not necessary for you to provide your social security number when you enroll as a member of the Washington State Twin Registry. This number can help us find you if you move or lose contact with us. If you do provide it, your social security number is kept confidential.