Identifying as both male and female. Shortened to "DB". From "Double" meaning "at or to twice the amount or extent" and "Binary" meaning "relating to, composed of, or involving two things".
"What gender do you identify as?" "I am male-female bigender. I am double-binary."
Also Double-Binary Visibility Day and Double-Binary Awareness Day.
January 26th.
Origin: International Women's Day and International Men's Day added together
Happy Double-Binary People's Day!