Spanish countries do it for years with "@" or "x" like "estimad@s" for "estimados" and "estimadas" at once. And Latin America is not very politically correct, it's just respectful for all genders.
In writing only, and very obnoxious as well for a culture that fights for their grave accents and correct language way more than their English counterpart.
Otherwise tell me how do you say niñ@s out loud.