Includes a newsletter, registry for twins, study information and conferences.

Events, journal, bylaws, membership information.

A longitudinal sociological study of twins born in the new millennium.

If you and your twin are over the age of 18, live in the Bay Area, and are interested in registering, you will be invited to participate in studies and be eligible to receive payment for your participation.

Recognized internationally as a unique resource for research and information about the causes, effects and problems of multifetal pregnancy.

A long-term study of language development in twins. The goal of the project is to compare language learning in identical and fraternal twins to determine which aspects of language and language learning have a heritable basis.

Newsletter, research information, survey.

Journal of the International Society for Twin Studies. Topics covered in the journal include behavioral genetics, complex diseases, endocrinology, fetal pathology and other areas of research.

Located at St Thomas' Hospital, London, UK.

From the Institute of Behavioral Genetics at the University of Colorado. A handful of studies for twins of all ages.

An unpublished dissertation on twins and studies in homosexuality.

A twin survey on personality, conducted by researchers at Virginia Commonwealth University.