Most research on trends in socio-economic fertility differences has focused on cohort total fertility and on women. This study aimed to analyse how cohort trends in parity-specific fertility differ across educational segments for men and women and what role multi-partner fertility plays in these trends. We used Finnish and Swedish register data on cohorts born in 1940–73/78. The main analyses used parity progression ratios, comparing ordinary ratios with similar ratios using births to first reproductive partners only. Among the low and medium educated, we observe strengthening parity polarization across cohorts, with increases in both childlessness and births of order three or higher, the latter largely reflecting increases in multi-partner fertility. Highly educated men and women more often have exactly two children. We demonstrate that cohort total fertility can mask significant parity-specific trends across educational groups and that changes in multi-partner fertility can play a part in cohort trends in socio-economic fertility differentials.

大多数关于社会经济生育率差异趋势的研究都集中在队列总生育率和女性身上。本研究旨在分析男性和女性在不同教育领域中特定生育率的队列趋势有何不同，以及多伙伴生育率在这些趋势中的作用。我们使用了 1940-73/78 年出生的队列的芬兰和瑞典登记数据。主要分析使用胎次进展比率，将普通比率与仅使用第一生殖伴侣的出生率进行比较。在受教育程度低和中等的人群中，我们观察到群体之间的均等两极分化加剧，无子女和三级或更高出生率的增加，后者在很大程度上反映了多伴侣生育率的增加。受过高等教育的男性和女性通常正好有两个孩子。