Yes! "Rubia" is the feminine form of "rubio." As with many Spanish adjectives, you can just change the final "o" to an "a" when you want to use it to describe a female. AnswerParty!
The Spanish language uses adjectives in a similar way to English and most other Indo-European languages. Spanish adjectives usually go after the noun they modify, and they agree with what they refer to in terms of both number (singular/plural) and gender (masculine/feminine).
Spanish adjectives are very similar to nouns, and often interchangeable with them. A bare adjective can take an article and be used in the same place as a noun (where English would require nominalization using the pronoun one(s)). For example:
In linguistics, grammatical gender is a system of noun classification present in approximately one fourth of the world's languages. In these languages, every noun inherently carries one value of the grammatical category called gender; the values present in a given language (of which there are usually two or three) are called the genders of that language. According to one definition: "Genders are classes of nouns reflected in the behaviour of associated words."
Common gender divisions include masculine and feminine; masculine, feminine and neuter; or animate and inanimate. In a few languages, the gender assignation of nouns is solely determined by their meaning or attributes, like biological sex, humanness, animacy. However, in most languages, this semantic division is only partially valid, and many nouns may belong to a gender category that contrasts with their meaning (e.g. the word "manliness" could be of feminine gender). In this case, the gender assignation can also be influenced by the morphology or phonology of the noun, or in some cases can be apparently arbitrary.
Gender-neutrality in languages with grammatical gender
The Spanish language has nouns that express concrete objects, groups and classes of objects, qualities, feelings and other abstractions. All nouns have a conventional grammatical gender. Countable nouns inflect for number (singular and plural). However, the division between uncountable and countable nouns is more ambiguous than in English.
All Spanish nouns have one of two grammatical genders: masculine and feminine (mostly conventional, that is, arbitrarily assigned). Most adjectives and pronouns, and all articles and participles, indicate the gender of the noun they reference or modify.
Gender neutrality in languages with grammatical gender implies promoting language usage which is balanced in its treatment of the genders. For example, advocates of gender-neutral language challenge the traditional use of masculine nouns and pronouns ("man", "businessman", "he", and so on) when referring to two or more genders or to a person or people of an unknown gender in most Indo-European and Afro-Asiatic languages.