This study examines gender differences in altruism using a modified dictator game with varying incomes and prices. The findings reveal that the question "which is the fair sex?" has a complex answer: when altruism is costly, women are more generous, but when it is cheap, men are more altruistic. This indicates that the male and female "demand curves for altruism" cross, with men being more responsive to price changes. Additionally, men are more likely to be either perfectly selfish or perfectly selfless, while women tend to be "equalitarians" who prefer to share evenly. The experiment, conducted at the University of Wisconsin and Iowa State University, involved 142 subjects, with approximately two-thirds being male. The study used a modified dictator game where participants decided how to allocate tokens between themselves and another subject. The results showed that, on average, there was no significant difference in the amount passed between men and women. However, when examining the data in terms of relative prices and real income, significant differences emerged. Men increased the proportion of tokens given when the relative price of giving was favorable, while women decreased the proportion. The results also showed that men were more price-elastic in their altruistic behavior than women. The study also found that men were more likely to exhibit extreme behaviors, such as being perfectly selfish or perfectly selfless, while women were more likely to be equalitarians. These findings align with psychological research on gender differences in altruism. The study's results suggest that gender differences in altruism depend on the price of giving, and that these differences can have important implications for economic models and data analysis. The study's findings have implications for various areas, including charitable giving and restaurant tipping. The results suggest that men and women may have different price elasticities for altruism, which could affect tax policy and charitable giving. The study also highlights the importance of considering gender differences in experimental economics and the need for more attention to these differences in future research.This study examines gender differences in altruism using a modified dictator game with varying incomes and prices. The findings reveal that the question "which is the fair sex?" has a complex answer: when altruism is costly, women are more generous, but when it is cheap, men are more altruistic. This indicates that the male and female "demand curves for altruism" cross, with men being more responsive to price changes. Additionally, men are more likely to be either perfectly selfish or perfectly selfless, while women tend to be "equalitarians" who prefer to share evenly. The experiment, conducted at the University of Wisconsin and Iowa State University, involved 142 subjects, with approximately two-thirds being male. The study used a modified dictator game where participants decided how to allocate tokens between themselves and another subject. The results showed that, on average, there was no significant difference in the amount passed between men and women. However, when examining the data in terms of relative prices and real income, significant differences emerged. Men increased the proportion of tokens given when the relative price of giving was favorable, while women decreased the proportion. The results also showed that men were more price-elastic in their altruistic behavior than women. The study also found that men were more likely to exhibit extreme behaviors, such as being perfectly selfish or perfectly selfless, while women were more likely to be equalitarians. These findings align with psychological research on gender differences in altruism. The study's results suggest that gender differences in altruism depend on the price of giving, and that these differences can have important implications for economic models and data analysis. The study's findings have implications for various areas, including charitable giving and restaurant tipping. The results suggest that men and women may have different price elasticities for altruism, which could affect tax policy and charitable giving. The study also highlights the importance of considering gender differences in experimental economics and the need for more attention to these differences in future research.