(By Hannah J. Haynie): "A noun class/gender system categorizes nouns for the purposes of grammatical agreement with other constituents in the noun phrase or other inflectional morphology. See the classification wiki page for more information on our definition of noun class/gender. Noun class/gender assignment may be based on one or several factors. This feature focuses on whether the categories masculine and feminine are relevant for noun class/gender assignment in a given language. A contrast between these categories in a noun class/gender system serves as a minimal criterion for this feature to be coded 1. Languages that overtly mark only one of these categories (e.g. feminine, with an unmarked class interpreted as non-feminine) do encode the relevant distinction and should be coded 1. A language may encode other socially or culturally relevant gender distinctions, and there may be cross-linguistic and cross-cultural differences in the semantics and membership of masculine and feminine categories. A language may also categorize nouns based on other factors entirely (e.g. shape, animacy, phonological properties). For the purposes of this feature, grammatical categories other than masculine and feminine should be disregarded."
The use of these two specific categories in the definition of this feature is meant to enable consistent coding and interpretation of data for a narrowly-defined, cross-linguistically common distinction. This is not meant to represent social or cultural gender constructs or particular biological traits, nor is it intended to reflect the full diversity of grammatical gender systems. For more information on the difference between grammatical gender and social, cultural, and biological constructs or traits, see the gender wiki page."