autoidentificarse

To classify oneself as belonging to a particular group, category, or identity — common in surveys, sociology, and discussions of gender, ethnicity, or political affiliation: se autoidentifica como independiente.

• En la encuesta, el treinta por ciento se autoidentificó como independiente. — In the survey, thirty percent self-identified as independent.
• Prefiere no autoidentificarse con ninguna etiqueta rígida. — She prefers not to self-identify with any rigid label.
• El censo permite autoidentificarse según la propia percepción étnica. — The census allows people to self-identify according to their own ethnic perception.

Don't confuse it with the more casual identificarse (to show ID/identify oneself to someone), which has a completely different everyday meaning.

Often confused with identificarse.