The authors regret that the coding of the attitude items in the manuscript Using genetic information to test causal relationships in cross-sectional data was exactly reversed. The codebook that we were working from for the original paper was the opposite of the actual coding of the raw variables. The purpose of the paper was to present an empirical model for testing causal hypotheses using cross-sectional twin data. The data were used to present readers with an example of how to use the method. Accordingly, the impact of the coding error on the conclusions is minimal. Of course, this has the potential to cause confusion for individuals who are focused on the sign of the relationship between personality and sex attitudes and not on the causal structure.