Moto SUMITOMO's eldest son, Yoshio SUMITOMO, is also a doctor of engineering, having graduated from the Osaka University graduate school's doctoral course in basic engineering; however, since his uncle, family head Kichizaemon SUMITOMO, had no legitimate son to be an heir, Yoshio was adopted by the family head Kichizaemon.
住友元夫の長男住友芳夫（住友金属工業）も、阪大大学院基礎工学研究科博士課程卒業の工学博士であるが、伯父の当主住友吉左衛門に嫡男がいないため、当主吉左衛門の養嗣子となっている。