Prenatal testosterone and sexually differentiated childhood play preferences: a meta-analysis of amniotic fluid studies

Gareth Richards,Wendy V Browne

doi:10.1007/s12144-021-02386-z

Gareth Richards, Wendy V Browne

Open Access

https://doi.org/10.1007/s12144-021-02386-z

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Journal: Current Psychology	Publication Date: Jan 17, 2022
Citations: 2	License type: CC BY 4.0

Affiliation: Newcastle University, University of Cambridge

Abstract

Sexually differentiated behaviour appears to emerge from a complex interaction of biological and socio-cultural factors, with prenatal exposure to steroid hormones such as testosterone thought to play a key role. Due to large sex differences being present from a very early age, much research has focussed on the influence these hormones may have on play preferences during childhood. We present an overview of the literature and a random-effects meta-analysis linking amniotic testosterone with sexually differentiated play preferences (k = 9, n = 493). The overall effect size estimate was in the theory-consistent direction (i.e., with higher levels of testosterone associated with more male-typical play preferences), though not statistically significant (r = 0.082, p = 0.274). However, after three hypothesised missing studies were imputed via the trim and fill procedure, a significant correlation emerged (r = 0.166, p = 0.014). Nevertheless, one sample was observed to exert a particularly large influence on the outcome of the analysis. Notably this was the second biggest sample and related to the largest effect size estimate. Though far from conclusive, the overall findings are consistent with the idea that individual differences in prenatal testosterone within the typical range predict sexually differentiated play preferences in early life. However, these effects may be small in magnitude and appear to vary considerably across studies.

Highlights

Sex differences are present for a range of behaviours that emerge during early human development (Hines, 2004)
Todd et al (2018) reported similar findings for a metaanalysis (k = 16) of children’s toy choices during free play activities and noted that the effects were not moderated by a variety of social/cultural factors including the presence of an adult, the study context, the gender inequality index of the country in which the study was conducted, and the inclusion
The two-level meta-analysis (k = 9, n = 493) yielded a positive but non-significant effect size estimate, r = 0.082, p = 0.274 (Fig. 1 for forest plot)

Summary

Introduction

Sex differences are present for a range of behaviours that emerge during early human development (Hines, 2004). Sex differences in human play behaviour manifest very early in life as a male inclination towards ‘rough-and-tumble’ (e.g., play fighting), and preferences by both boys and girls for same-sex play partners and stereotypically sex-typical toys (e.g., vehicles for boys, dolls for girls). The magnitude of the sex difference for play behaviours appears to be large for toy preferences, which is larger than the size of the sex differences found in most areas of cognition and personality (Hines, 2010). A recent meta-analysis (k = 75) by Davis and Hines (2020) confirmed that boys prefer male-typical toys (d = 1.83) and girls prefer femaletypical toys (d = 1.60), that both boys (d = 3.48) and girls (d = 1.21) prefer gender-typical toys over gender-atypical toys, and that these effects are very large in magnitude.

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Conclusion