Interorganizational scholars have long thought about how firms learn through buyer relationships. However, it is not clear whether dyadic learning gains are susceptible to imitation or are only inherited and whether these gains decay over time or are of an enduring nature. In this paper, I import ideas from the organizational imprinting literature into the interorganizational literature and apply the knowledge-based and learning views of the firm to examine how suppliers with differing initial endowments learn to work together with a buyer. The findings from an inductive multiple case study of spinoff and nonspinoff suppliers of an automotive manufacturer parent in Turkey reveal the following three learning mechanisms: informal relationships and social capital, transfer of routines, and shared identity. Although nonspinoff suppliers also exhibit evidence of several learning processes to a certain extent, spinoff suppliers’ deeper relationship, in particular their shared identity, with their parent based on their direct parental heritage tends to be more difficult for them to copy. No matter how hard nonspinoff suppliers try, they have "one hand tied behind their back," they remain stepchildren, and they never truly become a biological child. By providing a novel setting and a rich set of qualitative data on the learning behaviors of these two types of suppliers, this study teases apart the knowledge and resources that can be "learned from external sources" versus those that can "only be inherited."