A hitherto unreported group of pregnancy fantasies, originally revealed to the staff members of an institution for wayward girls, is presented. Their origins are shrouded in the mysteries of “street” life. If an active lesbian thrusts her finger or tongue into the vagina of a menstruating partner, the menstrual blood coagulates quickly. Within a few weeks it is then expelled as an amorphous non viable mass, called a “Jelly Baby,” disposed of by flushing it down the toilet. An abortion or miscarriage, usually self-induced, may also be labelled a “Jelly Baby.” Jelly Baby stories were later related by former Youth Hcuse inmates, during group therapy sessions that took place on an acute adolescent receiving service in a general hospital; by then, the Jelly Baby story had undergone some change and elaboration. The authors speculate that the Jelly Baby fantasies are highly overdetermined condensations with genital and pregenital determinants, which may, at least in part, be related to distorted childhood theories of conception and birth. Personnel who work with delinquent female adolescents should be alerted to the fantasies, which may well be widespread. Further psychotherapeutic exploration of the life history of youngsters who believe in Jelly Babies is crucial to validate and/or expand upon our work.