Investigations of women’s same-sex relationships present a paradoxical pattern, with women generally disliking competition, yet also exhibiting signs of intrasexual rivalry. The current article leverages the historical challenges faced by female ancestors to understand modern women’s same-sex relationships. Across history, women were largely denied independent access to resources, often depending on male partners’ provisioning to support themselves and their children. Same-sex peers thus became women’s primary romantic rivals in competing to attract and retain relationships with the limited partners able and willing to invest. Modern women show signs of this competition, disliking and aggressing against those who threaten their romantic prospects, targeting especially physically attractive and sexually uninhibited peers. However, women also rely on one another for aid, information, and support. As most social groups were patrilocal across history, upon marriage, women left their families to reside with their husbands. Female ancestors likely used reciprocal altruism or mutualism to facilitate cooperative relationships with nearby unrelated women. To sustain these mutually beneficial cooperative exchange relationships, women may avoid competitive and status-striving peers, instead preferring kind, humble, and loyal allies. Ancestral women who managed to simultaneously compete for romantic partners while forming cooperative female friendships would have been especially successful. Women may therefore have developed strategies to achieve both competitive and cooperative goals, such as guising their intrasexual competition as prosociality or vulnerability. These historical challenges make sense of the seemingly paradoxical pattern of female aversion to competition, relational aggression, and valuation of loyal friends, offering insight into possible opportunities for intervention.

对女性同性关系的调查呈现出一种自相矛盾的模式，女性普遍不喜欢竞争，但也表现出性内竞争的迹象。目前的文章利用女性祖先所面临的历史挑战来理解现代女性的同性关系。纵观历史，女性在很大程度上被剥夺了独立获得资源的机会，通常依赖男性伴侣来养活自己和孩子。因此，同性同龄人成为女性在与有能力并愿意投资的有限合伙人竞争吸引和维持关系的主要浪漫对手。现代女性表现出这种竞争的迹象，不喜欢和攻击那些威胁她们浪漫前景的人，特别针对那些外表有吸引力和性不羁的同龄人。然而，妇女还相互依赖以获得援助、信息和支持。由于历史上大多数社会群体都是父权制的，因此在结婚后，妇女离开家庭与丈夫同住。女性祖先可能使用互惠利他主义或互惠主义来促进与附近无关女性的合作关系。为了维持这些互惠互利的合作交流关系，女性可能会避开竞争激烈和追求地位的同龄人，而更喜欢善良、谦逊和忠诚的盟友。那些设法同时争夺浪漫伴侣并建立合作女性友谊的祖先女性会特别成功。因此，女性可能已经制定了实现竞争和合作目标的策略，例如将她们的性内竞争视为亲社会性或脆弱性。