*2.2. Clinical Characteristics and Demographics*

Child's height was measured to the nearest 0.1 cm using a stadiometer and weight to the nearest 0.1 kg using a calibrated digital scale. BMI was calculated using the standard formula, weight (kg) divided by height (m2). BMI z-scores and BMI percentiles (age and sex-specific standard deviation scores) were determined based on Center for Disease Control (CDC) standards [32]. Participants were given the option of having Tanner stage assessed by physical exam [33,34] and/or by a validated sex-specific assessment questionnaire for children and parents, containing both illustrations and explanatory text [35]. Forty-eight participants opted for both physical exam and questionnaire, and 55 participants opted for self-reported puberty status only. The correlation between Tanner Staging assessed by physical exam and by questionnaire was 0.91.

Socioeconomic status (SES) was assessed using household income at birth, estimated based on census tract of residence and expressed as a continuous variable, and maternal education at birth, which was extracted from birth certificates in the EMR as a categorical variable with the following categories: "high-school or some high-school", "some college", and "college and post-education". Prenatal exposures to maternal gestational diabetes mellitus (GDM) and maternal pre-pregnancy BMI were assessed using the EMR.
