We study the opinions on prostitution that emerged from the World Value Survey. We show that individuals tends to justify prostitution more in countries where it is legal or regulated and less in countries where it is prohibited, even after controlling for religious, cultural and sociological factors. To overcome the endogeneity of the policy to the opinions, we propose an instrumental variable strategy, instrumenting prostitution policy with legal origins. At least for the case of prostitution, policies seem to affect opinions.