Testosterone trade-offs and partnering in women and men

Previous research has shown that partnered heterosexual men have lower testosterone than single heterosexual men. Whether this pattern is apparent beyond heterosexual men has not been examined, and there is, as of yet, little empirical basis for directional interpretations. To address these issues, three studies were conducted in which the partnering-testosterone link was examined in diverse samples of North American men and women. In the first study, cross-sectional results showed that testosterone and partnering were associated in heterosexual men and non-heterosexual women, as partnered individuals in these groups exhibited lower testosterone than their unpartnered counterparts. No significant difference in testosterone by partnered status was found in heterosexual women or non-heterosexual men. Longitudinal results showed that lower testosterone predicted entering relationships, and there was no evidence that changes in relationship status influenced testosterone. In the second study, findings indicated that physical partner presence was associated with lower testosterone for women, but not men. In the third study, polyamory (having multiple, committed relationships) was associated with higher testosterone for both men and women. Neither sexual desire nor sociosexual orientation (willingness to engage in sexual contact outside a committed relationship) explained these associations. These studies are discussed within a framework of testosterone trade-offs between high testosterone and ‘competitive’ (resource acquisition/defence) behaviours versus low testosterone and ‘bond-maintenance’ (intimacy) behaviours. Interpretations of results from these studies point more strongly towards a trait effect (such that testosterone affects partnering, or ‘relationship orientation’) than a state effect (such that partnering would affect testosterone, or ‘relationship status’).