abstract: The presence of certain chromosomal disorders is not always immediately apparent at birth. Children with relatively high-incidence, but non-heritable disorders may receive delayed identification due to the sometimes subtle manifestation of their disorder. Delayed identification may result in various undesirable outcomes for affected children and their families. In addition to parents, teachers can be valuable participants in the identification process. Chromosomal disorders are associated with generally predictable physical and behavioral characteristics, known as phenotype. In the present study, the influence of phenotype on teachers' student-related concerns was examined. Teachers looked at a photo and read a vignette about a fictional elementary-age student who, although not identified, showed varying degrees of the Turner syndrome phenotype. A follow-up questionnaire indicated significantly greater concerns when a student showed many versus few characteristics of behavioral phenotype. However, the effect of morphological phenotype on teacher responses was not significant. The implications for identification of chromosomal disorders are discussed. / Dissertation/Thesis / Ph.D. Educational Psychology 2013