Problems arise when selecting a personal pronoun to refer to someone of unspecified or unknown gender (see also above). In the past and to some degree still in the present, the masculine has been used as the "default" gender in English. The use of the plural pronoun "they" with singular reference is common in practice. The neuter "it" may be used for a baby but not normally for an older child or adult. (Other genderless pronouns exist, such as the impersonal pronoun "one", but they are not generally substitutable for a personal pronoun.) For more information see Gender-neutral language and Singular "they".