Which anthropometric index does NOT differ between genders?

Body Mass Index (BMI) is the correct choice because it is a universal measure that is calculated from an individual's weight and height, making it gender-neutral in its application. The formula for BMI is weight in kilograms divided by height in meters squared, which means it does not require differentiating factors based on gender to compute. As a result, it provides a standardized approach to assessing body weight relative to height across all individuals.

In contrast, other anthropometric indices such as waist circumference, waist to hip ratio, and skinfold thickness tend to exhibit differences between genders due to variations in body composition, fat distribution, and physiological factors. Males and females typically store fat in different patterns (e.g., males often have more abdominal fat while females may have more hip and thigh fat), which influences these measurements. Consequently, measurements like waist circumference and skinfold thickness can vary significantly between men and women, whereas BMI remains consistent across genders.