Comments on the article by E. Diener, R. E. Lucas, and C. N. Scollon (see record 2006-05893-003) which cited a study by Tellegen et al. in which the Well-Being scale of the Multidimensional Personality Questionnaire (MPQ), administered to 44 pairs of monozygotic reared-apart (MZA) twins, yielded a within-pair correlation of 0.48. I contend that, in their subsequent proposed changes to subjective well-being (SWB) theory, Diener et al. failed to incorporate the implications of this heritability.