Organized youth sport is a relatively common family context in which sibling dynamics are not well understood. The present study was designed to address two contrasting mechanisms of socialization—modeling and differentiation—in examining older siblings’ influence on younger siblings’ sport participation. American youth (N = 221) age 10–15 years (M = 12.38, SD = 1.01) who were active sport participants completed an online survey measuring individual and family demographics, sibling relationship qualities, and parent–child relationship dimensions. The participants reported on their most proximal older siblings, all of whom were within 4 years of age. The analyses suggest that sibling differentiation dynamics decreased the likelihood of playing the same primary sport as an older sibling for (a) the same biological sex, close in age to siblings; (b) the same biological sex, further in age from siblings; and (c) mixed biological sex, wide in age from siblings. The “Discussion” section highlights the practical value of understanding the impact of sibling influence processes on the individual, sibling dyad, and family system.

有组织的青少年运动是一种相对常见的家庭环境，其中兄弟姐妹的动态尚不清楚。本研究旨在解决两种截然不同的社会化机制——建模和分化——以检验年长的兄弟姐妹对弟弟妹妹体育参与的影响。 积极参加体育运动的 10-15 岁美国青少年 ( N = 221) ( M  = 12.38，SD = 1.01) 完成了一项在线调查，测量个人和家庭人口统计数据、兄弟姐妹关系质量和亲子关系维度。参与者报告了他们最近的兄弟姐妹，他们的年龄都在 4 岁以内。分析表明，兄弟姐妹的分化动态降低了与年长的兄弟姐妹进行相同主要运动的可能性：（a）生物性别相同，年龄接近兄弟姐妹；(b) 生物性别相同，但年龄相差较大的兄弟姐妹；(c) 混血，年龄与兄弟姐妹相差很大。“讨论”部分强调了理解兄弟姐妹影响过程对个人、兄弟姐妹二人组和家庭系统的影响的实际价值。