As they are the higher-investing sex, females tend to be slightly more demanding when picking a mate (as predicted by parental investment theory).[1] They also tend to have a more difficult task of evaluating a male's reproductive value accurately based on physical appearance, as age tends to have fewer constraints on a male's reproductive resources.[2] Buss attributed the older age preference to older males displaying characteristics of high providing-capacity[3] such as status and resources.[4] In terms of short-term and long-term mating, females tend to be oriented towards long-term mating due to the costs incurred from short-term mating.[5] Although some of these costs will be the same for males and females (risk of STIs and impairing long term mate value), the costs for women will be more severe due to paternity uncertainty (cues of multiple mates will be disfavoured by males).[43]