Flourishing is when an individual perceives that their life is going smoothly. It encompasses the hedonic and eudaimonic aspects of well-being: feeling good and functioning well (Huppert & So, 2013; Keyes & Annas, 2009). The correlation of the construct with indicators of adjustment and positive development makes it an attractive concept to assess well-being (Huta & Ryan, 2010; Keyes, 2007; Keyes et al., 2012). Emerging adulthood is a developmental stage that has arisen in western countries as a result of social and economic changes in recent decades. It describes a period that begins in late adolescence and lasts well into the third decade of life (Arnett, 2000). Studies focused on this stage, considered crucial in the determination of people's health and well-being pathways (Chen et al., 2019), have found an association between the adjustment of emerging adults and positive family relationships. It seems that family continues to have a major influence on young people's development (Fingerman & Yahirun, 2016) during emerging adulthood as well. Specifically, positive family relationships are associated with high levels of psychological well-being during the third decade of life (Zupančič et al, 2014). The main objective of this study is to examine the association between flourishing and family variables during emerging adulthood from a gender perspective and using longitudinal analysis. Therefore, this work has two specific goals: first, to examine the stability of the flourishing of emerging adults throughout the initial years (Wave 1) and intermediate years (Wave 2) of emerging adulthood, and second, to analyze whether family relationships were associated with the flourishing of emerging adults. A longitudinal study was carried out at two time points: wave 1 (Mean: 20.31; SD: 2.04) and (three years later) wave 2 (Mean: 23.66; SD: 2.08). The sample comprised 400 emerging adults (268 women) from the Transition to Adulthood in Spain research project (TAE) who completed a questionnaire assessing their perceptions of the quality of their family relationships (parental social support, parental involvement, parental warmth, parental autonomy support, and behavioral and psychological control) and their level of flourishing. The results show the stability of the flourishing between W1 and W2. They also show a statistically significant relationship between flourishing and family variables and interesting gender differences. The crucial role that family also has during emerging adulthood is highly reflected in the results
