PT - JOURNAL ARTICLE AU - Falck-Ytter, Terje AU - Hamrefors, Linnea AU - Sanchez, Monica Siqueiros AU - Portugal, Ana Maria AU - Taylor, Mark AU - Li, Danyang AU - Viktorsson, Charlotte AU - Hardiansyah, Irzam AU - Myers, Lynnea AU - Westberg, Lars AU - Bölte, Sven AU - Tammimies, Kristiina AU - Ronald, Angelica TI - Babytwins Study Sweden (BATSS): A multi-method infant twin study of genetic and environmental factors influencing infant brain and behavioral development AID - 10.1101/2021.04.19.439492 DP - 2021 Jan 01 TA - bioRxiv PG - 2021.04.19.439492 4099 - http://biorxiv.org/content/early/2021/04/20/2021.04.19.439492.short 4100 - http://biorxiv.org/content/early/2021/04/20/2021.04.19.439492.full AB - Twin studies can help us understand the relative contributions of genes and environment to phenotypic trait variation including attentional and brain activation measures. In terms of applying methodologies like electroencephalography (EEG) and eye tracking, which are key methods in developmental neuroscience, infant twin studies are almost non-existent. Here we describe the Babytwins Study Sweden (BATSS), a multi-method longitudinal twin study of 177 MZ and 134 DZ twin pairs (i.e. 622 individual infants) covering the 5 - 36 month time period. The study includes EEG, eye tracking and genetics, together with more traditional measures based on in-person testing, direct observation and questionnaires. The results show that interest in participation in research among twin parents is high, despite the comprehensive protocol. DNA analysis from saliva samples was possible in virtually all participants, allowing for both zygosity confirmation and polygenic score analyses. Combining a longitudinal twin design with advanced technologies in developmental cognitive neuroscience and genomics, BATSS represents a new approach in infancy research, which we hope to have impact across multiple disciplines in the coming years.Competing Interest StatementThe authors have declared no competing interest.