Table 1:

Gender Terminology – definitions and assessment in the ABCD study.

	Definition	Item in ABCD Study
SEX	The assignment as male or female, usually based on physical anatomy and/or chromosomes at birth.	What sex was your child assigned at birth, on the original birth certificate?a
GENDER	The social expectations placed on individuals based on their sex.	-
GENDER IDENTITY	Internal sense of oneself as boy, girl, or something else.	-
CISGENDER	Individuals whose gender identity is sex-congruent	Not asked
TRANSGENDER	Individuals whose gender identity differs from the sex they were assigned at birth	Are you transgender?b
ASSESSED IN THE QUANTITATIVE, MULTI-DIMENSIONAL GENDER SURVEY
Dimension	Definition	Itemc
FELT-GENDER	The degree of feeling (or not) like the gender aligned with sex and the gender aligned with the opposite sex. Felt gender can be sex-congruent or not.	How much do you feel like a girl?
		How much do you feel like a boy?
GENDER EXPRESSION	The communication of gender through appearance, mannerisms, etc. Gender nonconformity is assessed in this study.	How much have you dressed/acted as a boy during play?
GENDER CONTENTEDNESS	Happiness with being the gender aligned with sex. Gender non-contentedness is assessed in this study.	How much have you had the wish to be a boy?

^a.Parent-report demographic survey.

^b.Youth-report KSADS-5 background item.

^c.The female version of the multi-dimensional gender survey; male items are identical with opposite gendered nouns.