In this chapter, we describe findings from a retrospective interview study with parents one to two years after they participated in HSE. Through qualitative analysis of the interviews, three distinct interest pathways emerged: (a) engineering focused, (b) prior interest focused, and (c) family values focused. The findings problematize traditional approaches to studying STEM-related interests and highlight the importance of understanding the complex ways families make sense of and engage with STEM through play and other informal learning experiences.