Sibling and Twin Relationships Survey

The purpose of this research is to learn more about twin and sibling relationships and their impact on relationship development.

You must have a sibling and be 18 years of age or older to participate in this study.

If you agree to be in this research, we will ask you to spend approximately 20 minutes filling out a series of questionnaires. If you are unable to complete each set of questions in one sitting, you will have the opportunity to create a private user name and password so that you can return to this site at another time.

If you volunteer to be in this study, you may withdraw at any time without consequences of any kind. You may also refuse to answer any questions you don't want to answer and still remain in the study.

There are no anticipated risks to you for participating in this research. As a benefit of participating in this research, you may learn more about your relationships, and you will be helping the field of psychology by providing us with valuable data on these relationships.

The researchers conducting this study are Chris Fraley, PhD and Caroline Tancredy, M.A. You may ask any questions you have before you begin the study. If you have questions now or later, you may contact Caroline Tancredy by e-mail at cmtancredy@ucdavis.edu, or by phone at our research office at (773) 235-3016.

For New Participants

If you have not participated in this study before, you will need to create a user name and password below. Try to make your user name unique-- something that no one else would choose. Please limit your user name and password to 10 characters or less and please do not use spaces. Also, be sure to write it down; you will need to enter it each time you choose to work on the study. The user name and password will be case sensitive (i.e., lowercase vs. uppercase letters will be treated differently).

Create a User Name
Create a Password
Please check this box if you are a twin.


Please click the 'begin' button once you've created a new user name and password.

By clicking on this button I affirm that I am 18 years-of-age or older, I have read the above information, and that I am willing to participate in this research. I understand that I am under no obligation to participate in this research if I do not want to, and that I can quit the research at anytime.
For Returning Participants

If you already have a user name and password and would like to continue the study, please enter your user name and password below. Please keep in mind that the user name and password are case sensitive (i.e., lowercase vs. uppercase letters are different).

Enter Your User Name
Enter Your Password


Please click the 'Login' button once you've entered your user name and password.

By clicking on this button I affirm that I am 18 years-of-age or older, I have read the above information, and that I am willing to participate in this research. I understand that I am under no obligation to participate in this research if I do not want to, and that I can quit the research at anytime.