NOVELTY - A fuel cell (300) comprises gas diffusion medium (322) interposed between separator plate (302, 304) and membrane electrode assembly. The gas diffusion medium includes hydrophobic layer (324) formed adjacent the separator plate and in fluid communication with a flow field (306); and a hydrophilic layer (326) formed adjacent the membrane electrode assembly and in fluid communication with the membrane electrode assembly.    USE - For fuel cell power system.    ADVANTAGE - The invented fuel cell provides a balanced hydration of the proton exchange membrane along with maintenance during operation of full activity in the catalyst attached to the surfaces of the proton exchange membrane.    DETAILED DESCRIPTION - A fuel cell comprises separator plate including a flow field; membrane electrode assembly having an active area formed on a proton exchange membrane; and gas diffusion medium interposed between the separator plate and the membrane electrode assembly such that the active area is in reactive interface with the flow field. The gas diffusion medium includes hydrophobic layer formed adjacent the separator plate and in fluid communication with the flow field; and a hydrophilic layer formed adjacent the membrane electrode assembly and in fluid communication with the membrane electrode assembly. A reactant gas is transported in the reactant flow field and distributed to the active area through the gas diffusion media. An INDEPENDENT CLAIM is also included for a gas diffusion medium for a fuel cell comprising planar porous structure defining an in-plane direction and a through-plane direction. The porous structure provides a transport mechanism for reactant gas in the through-plane direction, It further includes a hydrophobic layer formed on a first surface of the porous structure and providing a transport mechanism in the gas diffusion media for moisture in the in-plane direction, and a hydrophilic layer formed on a second surface of the porous structure and providing a transport mechanism m the gas diffusion media for moisture in the through-plane direction.    DESCRIPTION OF DRAWING(S) - The figure is a cross-sectional view of fuel cell.    Fuel cell (300)    Separator plate (302)    Flow field (306)    Gas diffusion medium (322)    Hydrophobic layer (324)    Hydrophilic layer (326)