The occurrence of incest in which a female child is molested by an older male family member may be increasing as the number of stepfamilies increases, because previous evidence suggests that girls living with stepfathers are at greater risk for molestation. If psychotherapists will be seeing more incest-history clients as a result of this trend, then therapists' beliefs and perceptions about the role of incest in psychopathology must be explored. Questionnaires presenting incest and no-incest case histories and assessments of disturbance, prognosis and background factors were completed by 124 psychotherapists. Results showed that the presence of incest in a case history did not significantly affect therapists' ratings of level of disturbance and prognosis. Despite this lack of differences in perceptions of the client, therapists were significantly less willing to work with incest victims. Furthermore, when incest was mentioned in a case history, therapists were very likely to consider it a crucial cause of the client's disturbance and to give less attention to other background factors, such as infantilization and sibling rivalry. In rating incest clients, therapists also tended to give commensurately greater weight to other background factors believed to be associated with incest, such as "father's mental problems," suggesting that therapists manifest a strong preconception that incestuous fathers are mentally disturbed. (Author/NRB)