Abstract: Underwear for a human wearer, having adaptive leg openings and size-adjusting fabric-regions. A singular fabric- region of the undergarment is structured as a saddle, located beneath a crotch or gusset area, and extends downwardly along a portion of the upper inner right hip and the upper inner left hip. That fabric-region is formed of a fabric or yarns having a particular elasticity characteristic, that is different from the elasticity characteristics of other fabric-regions of that undergarment; and that provides an increased elasticity, and particularly an increased horizontal elasticity, to that saddle-structured fabric region.

Abstract: A male undergarment that comprises a body encircling member, including a front piece and a rear piece; an elastic waist band attached to the encircling member; a scrotum receiving section formed by a portion of the front piece and by an adjacent inwardly positioned piece of fabric and a pouch, adapted to retain the scrotum therein and defined by the scrotum receiving section and by a separate border element. The pouch is produced in such a way that the border element is attached to the scrotum receiving section. The border element is configured to contact the groin when the undergarment is worn, so as to reduce friction between the scrotum and groin.