International trade and the survival of mammalian and reptilian species.

The Convention on International Trade in Endangered Species (CITES) bans international trade in species threatened with extinction. We investigate the effects of these bans on species' endangerment, as assessed by the International Union for Conservation of Nature (IUCN). Our analysis exploits changes in CITES bans between 1979 and 2017. We find that CITES bans lead to subsequent improvements in mammalian species' IUCN status, relative to species in which trade was not banned. These effects are primarily due to improvements in the status of commercially targeted species. On the other hand, CITES bans lead to deteriorations in reptilian species' IUCN status. We find that major spikes in trade volume occurred in anticipation of the bans on reptilian species but not in anticipation of those on mammalian species.

Crystal Clear? The Relationship Between Methamphetamine Use and Sexually Transmitted Infections.

Public health officials have cited methamphetamine control as a tool with which to decrease HIV and other sexually transmitted infections, based on previous research that finds a strong positive correlation between methamphetamine use and risky sexual behavior. However, the observed correlation may not be causal, as both methamphetamine use and risky sexual behavior could be driven by a third factor, such as a preference for risky behavior. We estimate the effect of methamphetamine use on risky sexual behavior using monthly data on syphilis diagnoses in California and quarterly data on syphilis, gonorrhea, and chlamydia diagnoses across all states. To circumvent possible endogeneity, we use a large exogenous supply shock in the US methamphetamine market that occurred in May 1995 and a later shock stemming from the Methamphetamine Control Act, which went into effect in October 1997. While the supply shocks had large negative effects on methamphetamine use, we find no evidence that they decreased syphilis, gonorrhea, or chlamydia rates. Our results have broad implications for public policies designed to decrease sexually transmitted infection rates.

In sickness and in health: same-sex marriage laws and sexually transmitted infections.

This paper analyzes the relationship between same-sex marriage laws and sexually transmitted infections in the United States using state-level data from 1981 to 2008. We hypothesize that same-sex marriage laws may directly affect risky homosexual behavior; may affect or mirror social attitudes toward gays, which in turn may affect homosexual behavior; and may affect or mirror attitudes toward non-marital sex, which may affect risky heterosexual behavior. Our findings may be summarized as follows. Laws banning same-sex marriage are unrelated to gonorrhea rates, which are a proxy for risky heterosexual behavior. They are more closely associated with syphilis rates, which are a proxy for risky homosexual behavior. However, these estimates are smaller and less statistically significant when we exclude California, the state with the largest gay population. Also, laws permitting same-sex marriage are unrelated to gonorrhea or syphilis, but variation in these laws is insufficient to yield precise estimates. In sum, the findings point to a modest positive association--if any at all--between same-sex marriage bans and syphilis.

The economics of faking ecstasy.

In this paper, we develop a signaling model of rational lovemaking. In the act of lovemaking, a man and a woman send each other possibly deceptive signals about their true state of ecstasy. For example, if one of the partners is not in ecstasy, then he or she may decide to fake it. The model predicts that (1) a higher cost of faking lowers the probability of faking; (2) middle-aged and old men are more likely to fake than young men; (3) young and old women are more likely to fake than middle-aged women; and (4) love, formally defined as a mixture of altruism and demand for togetherness, increases the likelihood of faking. The predictions are tested with data from the 2000 Orgasm Survey. Besides supporting the model's predictions, the data also reveal an interesting positive relationship between education and the tendency to fake in both men and women.

Tolerance and HIV.

We empirically investigate the effect of tolerance for gays on the spread of HIV in the United States. Using a state-level panel dataset spanning the mid-1970s to the mid-1990s, we find that tolerance is negatively associated with the HIV rate. We then investigate the causal mechanisms potentially underlying this relationship. We find evidence consistent with the theory that tolerance for homosexuals causes low-risk men to enter the pool of homosexual partners, as well as causes sexually active men to substitute away from underground, anonymous, and risky behaviors, both of which lower the HIV rate.