Table 1.

A brief overview of the Minnesota Center for Twin and Family Research (MCTFR) studies

Study	Year Started	Twin/Sibling Pairs	Longitudinal Design
Minnesota Twin Family Study (MTFS)	1990	897 Monozygotic 485 Dizygotic	Two cohorts (initial age of 11 or 17) followed every 3-4 years through age-29
Sibling Interaction and Behavior Study (SIBS)	1998	408 Adopted 209 Full Biological	Cross-sectional sample first assessed in adolescence and followed twice through early adulthood
Enrichment Study (ES)	1999	300 Monozygotic 199 Dizygotic	First assessed at age-11 and followed at ages 14 and 17