"Service members who are eligible to be assigned to all positions for which they are qualified, except that women shall be excluded from assignment to units below the brigade level whose primary mission is to engage in direct combat on the ground as defined below. "Direct ground combat is engaging an enemy on the ground with individual or crew-served weapons, while being exposed to hostile fire and to a high probability of direct physical contact with the hostile force's personnel. Direct combat take place well forward on the battlefield while locating and closing with the enemy to defeat them by fire, maneuver, or shock effect."