For both aesthetic and practical reasons, that's the longtime standard in the modeling industry. A tall, slender body is considered a better "hanger" for a designer's clothes, both on the runway and in front of the camera (which really does add pounds). Clothing samples are cut to fit tall, slender bodies. For girls, that usually means clothes cut in sizes 4 to 6, fitting for a girl with a minimum height of 5 feet 7 inches. For guys, jacket sizes run from 40 to 42 and clothes are designed for who are minimum height of 5 feet 11 inches. Occasionally, an agency will accept shorter models (especially teenagers who wear large shoe sizes and have tall parents, in hopes that they will continue to grow). Some agencies also have divisions for petite and plus-size models, but the client demand is less for those categories.