||This paper studies how family systems condition kin influence on male reproduction in East Asia, taking advantage of new individual-level panel data comprising 4 million observations of 650000 individuals from northeast China, northeast Japan, southeast Korea and north Taiwan between 1688 and 1945. In addition to a revisit to our normative understanding of historical East Asian family systems, my big data comparisons reveal important details that define individual lifecourse experience within family domestic cycles. I apply multi-level models to compare the total family influence on individual reproduction, and to examine the effects of individual characteristics, specific co-resident kin, and family structure. Despite a helping effect of living with father, other kin effects vary greatly. However, comparatively, in joint-family populations the beneficial effects of living in a complex family always accompany the hindering effects of sibling competition, while in stemfamily populations neither makes a difference. Namely, no family system promotes reproduction better than others, and kin effects vary according to societal family systems. Long interweaving with local history and environment, different populations may have developed their own family system and demographic dynamics, which nevertheless lead to broad similarities in reproduction.