The young adulthood years are demographically dense. Dr. Ronald Rindfuss made this claim when he was Population Association of America (PAA) president in 1991 (Rindfuss 1991), and this conclusion holds today. I offer both an update of his work by including Millennials and a new view on young adulthood by focusing on an increasingly common experience: cohabitation. I believe we need to move away from our marriage-centric lens of young adulthood and embrace the complexity that cohabitation offers. The cohabitation boom is continuing with no evidence of a slowdown. Young adults are experiencing complex relationship biographies, and social science research is struggling to keep pace. Increasingly, there is a decoupling of cohabitation and marriage, suggesting new ways of framing our understanding of relationships in young adulthood. As a field, we can do better to ensure that our theories, methods, and data collections better reflect the new relationship reality faced by young adults.

中文翻译：

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不确定时代的年轻成年关系：同居案例。

年轻的成年时期人口密集。Ronald Rindfuss 博士在 1991 年担任美国人口协会 (PAA) 主席时提出了这一主张 (Rindfuss 1991)，这一结论在今天仍然成立。我通过将千禧一代包括在内来更新他的作品，并通过关注一种日益普遍的经历：同居来提供对青年期的新看法。我相信我们需要摆脱以婚姻为中心的年轻成年视角，并接受同居带来的复杂性。同居热潮仍在继续，没有放缓的迹象。年轻人正在经历复杂的人际关系传记，而社会科学研究正在努力跟上步伐。同居和婚姻越来越脱钩，这表明我们可以通过新的方式来构建我们对青年时期关系的理解。作为一个领域，