<p>The study of partner resemblance has widespread implications in the social and natural sciences. To date, the vast majority of such research has focused on opposite-sex couples. This study compared patterns of partner correlations (“assortment”) across 66 traits in the UK Biobank (UKB) in 89,628 female-male (FM), 236 female-female (FF), and 216 male-male (MM) putative couples. The average FF, MM, and FM correlations were positive (indicating similarity rather than dissimilarity), though both same-sex partner types yielded significant correlations for only a minority of traits at the Bonferroni-corrected level. FM pairs showed more positive assortment (<i>p</i>_unadjusted&lt;2e-16) than did MM or FF pairs for year of birth and number of children. Much existing same-sex partner correlation research has reported less similarity for age in MM pairs compared to opposite-sex pairs, while some (though not all) of the literature has reported lower similarity for age in FF pairs than in FM pairs. Expanding knowledge about same-sex assortment can contribute to family-based genetic designs and relationship psychology research in addition to diversifying couple-centered treatment modalities. Finally, this research can help to identify how couple dynamics and shared systemic factors potentially relate to ageing-related outcomes, behavior change, and healthcare needs in the LGBT community.</p>