Problems in Psychiatric Genetic Research: A Reply to Faraone and Biederman

This article examines evidence cited in favor of the operation of genetic factors in attention-deficit hyperactivity disorder (ADHD). Like other psychiatric conditions, a belief in the genetic basis of ADHD is derived from the results of family, twin, and adoption studies. Because family studies are widely believed to be confounded by environmental factors, primary emphasis is placed on twin and adoption studies. ADHD twin studies depend on the validity of the equal environment assumption (EEA), which holds that the environments of identical (MZ) and fraternal (DZ) twins are the same. Here it is argued that however the EEA is defined, it cannot be accepted. Therefore, the greater similarity or concordance of MZ twins when compared to DZ twins is plausibly explained by environmental factors. Adoption studies constitute a third method for investigating the role of genetic factors in ADHD. It is argued that these studies are greatly flawed by factors including non blinded diagnoses and the failure to study the biological relatives of adoptees. After an examination of the total weight of evidence in favor of a genetic basis or predisposition for ADHD, it is concluded that a role for genetic factors is not supported and that future research should be directed toward psychosocial causes     

Capability as Opportunity: How Amartya Sen Revises Equal Opportunity

Although the concept of equal opportunity has received scant attention from theological ethics, it attracts widespread approval in the U.S. popular culture and has been examined extensively by contemporary moral philosophy. Amartya Sen's conception of capabilities as "freedom" or "real opportunity" corrects deficiencies in both popular and philosophical conceptions of equal opportunity that ignore interpersonal variations in mental, physical, and psychological abilities beyond agents' control. Recent theologically informed conceptions of love and common grace affirm and revise Sen's conception of equal capability as equal opportunity. The resulting understanding of equal opportunity is quite different from some uses of this concept and could be an important criterion for a just society.