About The Louisville Twin Study

Louisville Twin Study Image

The Louisville Twin Study is internationally recognized as one of the oldest, largest, and most comprehensive studies of child development related to multiple birth status. Participants contributed significantly to our understanding of the complex interactions between genes and the environment. Twin and family studies provide a unique method to examine the many factors that contribute to developmental and health outcomes of children and to understand the underlying processes responsible for individual differences in those outcomes.

We appreciate the willingness of the former participants to take part in such an important project. We also appreciate the creativity, dedication, and hard work of the former researchers and staff members who worked diligently over many years to develop and execute the studies that make up the Louisville Twin Study.


We are currently enrolling past participants in a project we are calling the midlife extension of the Louisville Twin Study. Twins who participated in the past at any age are invited to participate. The study consists of health surveys, cognitive and physical measurements that can all be completed on one visit; we are flexible and will work with your schedule. Our study staff have received their COVID-19 vaccine series and we are following CDC and local requirements to keep you safe. We are happy to offer compensation up to $100 for twin’s time and effort.

Twins! Please let us know the best way to keep in touch! Email us at twins@louisville.edu, call 852-9191 or complete this form:  https://is.gd/TwinStudyForm