Gendered Body Mass Index Percentile Charts and Transgender Youth: Making the Case to Change Charts.

Body mass index (BMI) is defined as weight (kg)/height (m). Differences in BMI percentiles between sexes confound the diagnosis of weight-related disorders in transgender youth because choosing the appropriate chart is challenging. Data on BMI measures are needed for transgender youth, but there are no guidelines on how to collect or report this data. We use two theoretical cases to assert that health care providers and researchers should consider use of both male and female growth charts for transgender youth, particularly for individuals at the extremes of weight.