Embryo donation produces a family structure where neither rearing parent is genetically related to the child, as in adoption. It is not known how embryo donation parents view the donors compared with how adoptive parents view the birth parents. 21 couples with an embryo donation child aged 2-5 years were compared with 28 couples with an adopted child. Parents were administered a semi-structured interview, assessing knowledge of the donors/birth parents, frequency of thoughts and discussions about the donors/birth parents and disclosure of the donor conception/adoption to the child. Comparisons were made between mothers and fathers to examine gender differences. Embryo donation parents generally knew only the donors' physical characteristics, and thought about and talked about the donors less frequently than adoptive parents thought about and talked about the birth parents. Embryo donation fathers tended to think about the donors less often than did mothers. Disclosure of the child's origins in embryo donation families was far less common than in adoptive families (P < 0.001 for mothers and fathers), and was associated with the level of donor information (P < 0.05 for mothers, P < 0.025 for fathers). Embryo donation parents' views on the donors differ from adoptive parents' views on the birth parents, with donors having little significance in family life once treatment is successful.