It is proposed that poorly integrated sexual feelings between mother and daughter are frequent early precursors of later incestuous interactions between father and daughter. Father-daughter molestation may be seen as an enactment of erotic urges and fantasies between mother and daughter that find origin in pre-Oedipal, mother-child qualities of relatedness. The familial menage-a-trois is an intrapsychic and interpersonal compromise for mother and daughter between a more deeply disturbed and a more fully severed internal and external bond; it allows both partners enough distance from their dissociated feelings to feel safe, enough proximity to feel vicariously connected, and enough libidinization to maintain an alliance with the exciting object.