Something or someone is gendered when exhibiting gender-differentiated patterns.
Pink and blue as gendered colours, gendered institutions, gendered appearances, etc.
Additional notes and information
The usage of gender as a verb ( ‘gendering’, ‘engendered’, etc.) is a reflection of a changed understanding of gender as an active ongoing process – something is gendered when it is actively engaged in social processes that produce and reproduce distinctions in gender identities.
Pilcher, J., and Whelehan, I. (2004). Fifty Key Concepts in Gender Studies. London, Thousand Oaks.