This paper presents the findings of the third phase of a longitudinal study of families created by assisted reproduction. The quality of parent-child relationships was examined close to the adolescent's 18th birthday in 26 "in vitro" fertilization (IVF) families and 26 donor insemination (DI) families in comparison with 38 adoptive families and 63 natural conception families matched for demographic characteristics. A significantly higher level of mother-adolescent warmth was found between the assisted reproduction and the adoptive families, between the DI and natural conception families and between the DI and IVF families. IVF mothers showed significantly greater disciplinary indulgence than natural conception mothers, and significantly lower disciplinary aggression than DI mothers. No differences were identified between fathers for warmth or conflict. Only 2 DI children were aware of their donor conception. (Contains 2 tables.)