Abstract

Three reservations about Keller & Miller's (K&M's) argument are explored: Serious validity problems afflict epidemiological criteria discriminating disorders from non-disorders, so high rates may be misleading. Normal variation need not be mild disorder, contrary to a possible interpretation of K&M's article. And, rather than mutation-selection balance, true disorders may result from unselected combinations of normal variants over many loci. (Published Online November 9 2006).