Identity matters. You have the right for your Green Card gender marker to match your identity. While the US federal government still only recognizes two genders - female and male - you have the right to have your green card match your identity. This is true even if your passport may not reflect your gender identity (for instance, in countries without LGBTQIA+ rights). A wide variety of licensed professionals can fill out the form needed by USCIS: social workers, counselors, medical and osteopathic doctors, nurse practitioners, psychologists, physician assistants, and therapists.