▁valid ▁measurement ▁of ▁male ▁ar ous al . ▁More ▁recently , ▁therm ography ▁has ▁been ▁developed ▁to ▁measure ▁the ▁phys i ological ▁measurements ▁of ▁sexual ▁ar ous al . ▁Studies ▁have ▁found ▁temperature ▁change ▁specific ▁to ▁the ▁gen it als ▁during ▁sexual ▁ar ous al , ▁which ▁supports ▁the ▁valid ity ▁of ▁this ▁measure . ▁ ▁Fem ales ▁ ▁Sex ual ▁ar ous al ▁in ▁women ▁is ▁character ized ▁by ▁v aso cong estion ▁of ▁the ▁gen ital ▁t issues , ▁including ▁internal ▁and ▁external ▁areas ▁( e . g ., ▁ ▁v ag inal ▁walls , ▁cl itor is , ▁and ▁lab ia ). ▁There ▁are ▁a ▁variety ▁of ▁methods ▁used ▁to ▁assess ▁gen ital ▁sexual ▁ar ous al ▁in ▁women . ▁V ag inal ▁phot ople th ys m ography ▁( V PG ) ▁can ▁measure ▁changes ▁in ▁v ag inal ▁blood ▁volume ▁or ▁ph as ic ▁changes ▁in ▁v aso cong estion ▁associated ▁with ▁each ▁heart be at . ▁Cl itor al ▁phot ople th ys m ography ▁functions ▁in ▁a ▁similar ▁way ▁to ▁V PG , ▁but ▁measures ▁changes ▁in ▁cl itor al ▁blood ▁volume , ▁rather ▁than ▁v ag inal ▁v aso cong estion . ▁Th erm ography ▁provides ▁a ▁direct ▁measure ▁of ▁gen ital ▁sexual ▁ar ous al ▁by ▁meas uring ▁changes ▁in ▁temperature ▁associated ▁with ▁increased ▁blood ▁flow ▁to ▁the ▁external ▁gen ital ▁t issues . ▁Similarly , ▁lab ial ▁therm istor ▁cli ps ▁measure ▁changes ▁in ▁temperature ▁associated ▁with ▁gen ital ▁eng org ement ;