Personality plays a crucial role in mental health and adjustment to major life experiences. It affects whether individuals do or do not have children and how they deal with pregnancy and parenthood. Early research conducted more than 50 years ago primarily examined the predictive role of maternal neuroticism during and after pregnancy. More recent studies broadened their focus on the Big Five openness, conscientiousness, extraversion, agreeableness, and emotional stability (i.e. reverse neuroticism) and other personality traits. For example, there is evidence that individuals being less open to experiences are more likely to start a family (Asselmann & Specht, Citation2021; Denissen et al., Citation2019; van Scheppingen et al., Citation2016) and that more extraverted and emotionally stable women experience less fear of childbirth (Asselmann et al., Citation2021) and fewer psychopathological symptoms during the perinatal period (Asselmann et al., Citation2020).

Importantly, personality not only predicts but also changes due to life experiences (Denissen et al., Citation2019). In young adulthood, conscientiousness, agreeableness, and emotional stability tend to increase, a pattern referred to as the ‘maturity principle’ (Roberts et al., Citation2005). Contextual theories assume that such changes may (at least partly) result from age-graded life events (e.g. childbirth). The Social Investment Principle suggests that life events typically induce changes in social roles and role demands that require more ‘mature’ behaviour (Roberts & Wood, Citation2006). Because most people strive to adjust well and act accordingly, their personality might change. For instance, becoming a parent requires taking responsibility for a child, which might lead to higher levels of conscientiousness. Although frequently investigated, there is, however, surprisingly little support for this idea. Controlling for age effects, becoming a parent was mostly unrelated to Big Five changes or even linked to decreases in openness, conscientiousness, extraversion, or emotional stability, which is inconsistent with the ‘maturity principle’ (e.g. Asselmann & Specht, Citation2021; Denissen et al., Citation2019; Pusch et al., Citation2019; van Scheppingen et al., Citation2016).