2012 0-7734-2907-7 Most evidence about genetic behavior comes from twin studies. The presumption is that this enables an equal environment assumption (EEA). This book argues that the validity of the EEA argument is not as strong as some behavior geneticists have claimed. Felson conducts the most comprehensive evaluation of the EEA to date. His analysis incorporates a larger more diverse set of outcome variables than any previous research on the subject.