What are twin volunteers?

  • Center for Twin Research is a research institute specializing in the research of twins.
  • The Center recruits twin volunteers for studies, whose purpose is to scientifically analyze the similarities and differences between monozygotic and dizygotic twins and thereby contribute to the development of preventive medicine. Both monozygotic and dizygotic twins are warmly welcome to participate.
  • The persons who have decided to participate in the studies are called twin volunteers.


For more information about the research, see ”What can we learn from twin research”.

When you register yourself as a twin volunteer

You can participate in the clinical research

For the clinical research, a thorough medical examination will be conducted on both twins at the same time in order to map out the environmental and genetic factors related to the pair’s health and diseases. This research is expected to improve the health of a great number of people and contribute to our ability to prevent diseases in the future.

You can participate in the Center’s events

The Center organizes events for its registered twin volunteers. The events feature lectures from twin researchers and provide a place where twins can meet each other. For example, the Twin Festival of 2014 attracted roughly 200 twin participants, including 60 twin pairs.

You will receive our news letter

The Center publishes a newsletter called Twin Research News. It will be sent by mail to all of our twin registrants.

You will get to access the website’s registrant-exclusive contents

The Twin Volunteer Registrant Pages contain twin trivia known to all twins, event photo galleries and other registrant-exclusive content.

About the studies

You can decide whether or not to participate in studies or events case-by-case.

Questionnaires delivered by mail

Questionnaire studies are a research method whereby the Center mails you questionnaires that you can fill in and mail back in the attached return envelope. How often questionnaires will be sent varies, but no more than a couple will be sent per year. The questions focus on topics such as health, and eating habits, your daily living environment, work and social activities.

Clinical tests

For clinical tests, you will be asked to come to the Osaka University Hospital for blood tests, physical examination, zygosity test (to examine whether you are a monozygotic or dizygotic twins) and other tests that will be used as research material in subsequent studies.

Information regarding events organized by the Center

The Center organizes events where twin volunteers can meet each other. When such an event is organized, the Center will let send you information about it.