The aim of the study was to investigate family functioning and the psychological development of children raised in fatherless families from their first year of life. Thirty lesbian mother families and 42 families headed by a single heterosexual mother were compared with 41 two-parent heterosexual families using standardised interview and questionnaire measures of the quality of parenting and the socioemotional development of the child. The results show that children raised in fatherless families from infancy experienced greater warmth and interaction with their mother, and were more securely attached to her, although they perceived themselves to be less cognitively and physically competent than their peers from father-present families. No differences were identified between families headed by lesbian and single heterosexual mothers, except for greater mother-child interaction in lesbian mother families.