Research on the timing of events during the transition to adulthood, such as first union, sex, and birth in low- and middle-income countries (LMICs), focused predominantly on measures of central tendency, notably median or mean ages. In this report, we adopt a different perspective on this topic by examining disparities in the timing of these events in 46 LMICs spanning four decades. Using Demographic and Health Surveys, we estimate ages at which 25 percent, 50 percent, and 75 percent of women have first union, birth, and sex. We compute interquartile ranges to measure within-country variation and disparities in the timing of sexual initiation and family formation. Variation in the timing of first union, birth, and sex generally increases as the median ages at these events increase. Disparities in the timing of first union and birth grew in West Africa and Latin America, and women who experience these events relatively early increasingly lag behind women who experience them relatively late. Documenting trends in measures of central tendency is insufficient to capture the complexity of ongoing changes because they mask growing disparities in the timing of family formation across many LMICs. These results are important for assessing progress toward the achievement of sustainable development goals related to the reduction of early marriages and pregnancies and highlight a need for more holistic approaches to measure the timing of family formation.

中文翻译：

---

向成年期的不平等过渡：许多低收入和中等收入国家的初婚年龄、性别和出生年龄差距扩大

对中低收入国家 (LMIC) 向成年过渡期间事件发生时间的研究，例如第一次结合、性生活和出生，主要集中在集中趋势的测量上，特别是中位数或平均年龄。在本报告中，我们通过研究跨越四个十年的 46 个 LMIC 中这些事件发生时间的差异，对该主题采取了不同的观点。通过人口和健康调查，我们估计了 25%、50% 和 75% 的女性第一次结合、生育和发生性行为的年龄。我们计算四分位距来衡量国家内部在性开始和家庭形成时间方面的差异和差异。随着这些事件的中位年龄增加，第一次结合、出生和性别的时间变化通常会增加。在西非和拉丁美洲，第一次结合和生育时间的差异越来越大，经历这些事件的女性相对较早经历这些事件的女性越来越落后于经历这些事件的女性。记录集中趋势指标的趋势不足以捕捉正在进行的变化的复杂性，因为它们掩盖了许多 LMIC 家庭形成时间的日益增长的差异。这些结果对于评估实现与减少早婚和早孕相关的可持续发展目标的进展非常重要，并强调需要更全面的方法来衡量家庭形成的时间。记录集中趋势指标的趋势不足以捕捉正在进行的变化的复杂性，因为它们掩盖了许多 LMIC 家庭形成时间的日益增长的差异。这些结果对于评估实现与减少早婚和早孕相关的可持续发展目标的进展非常重要，并强调需要更全面的方法来衡量家庭形成的时间。记录集中趋势指标的趋势不足以捕捉正在进行的变化的复杂性，因为它们掩盖了许多 LMIC 家庭形成时间的日益增长的差异。这些结果对于评估实现与减少早婚和早孕相关的可持续发展目标的进展非常重要，并强调需要更全面的方法来衡量家庭形成的时间。