Australian Twin Registry - - Includes a newsletter, registry for twins, study information and conferences.
The Center for Study of Multiple Birth - - Recognized internationally as a unique resource for research and information about the causes, effects and problems of multifetal pregnancy.
Millennium Twins - - A longitudinal sociological study of twins born in the new millennium.
Sleep Research Study for Twins - - The University of Pennsylvania is recruiting same-sex twins living in the eastern time zone who are between the ages of 25 and 59 to participate in a sleep research study. [PDF.
Twin Research - - 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.
Twin Research - - Newsletter, research information, survey.