In this paper I argue that certain gender and class asymmetries attested in diminutive and augmentative formation in Brazilian Portuguese are better understood as markedness effects. I first discuss an asymmetry in augmentatives, where even though feminine base roots may form both masculine and feminine augmentative derivatives, masculine roots may only form masculine augmentatives. I then discuss a thematic class asymmetry, where even though diminutives preserve the class of the base when the base is either class I or class II, no class III diminutive is allowed, which I claim is due to class III's (relative) marked status when compared to classes I and II. To account for these markedness effects, I propose that features may become marked in the course of a morphosyntactic derivation, with particular syntactic contexts triggering markedness. In other words, markedness is seen as a property of the construction, rather than a general property of the language. The analysis presented here also provides support for the view that thematic classes are best represented as abstract properties of the root, rather than a property of the exponent.