Whilst there exists a considerable body of research documenting heterosexual couples' use of donor sperm, relatively little is known about the experiences of lesbian recipients of donor sperm and the men who donate to them. Moreover, in all aspects of donor conception there is an ongoing debate over what constitutes children's 'best interests', with this being most problematic in the unregulated private sector (of which lesbian use of donor sperm from gay men constitutes the largest portion). This article presents narratives of a sample of 16 gay men and one heterosexual man who had donated or who were in the process of donating sperm to lesbian recipients. Specifically, the article focuses on the ways in which the majority of the men elaborated a narrative in which their relationship to the birth mother was 'heterosexualised', a narrative that functioned to attribute to them a considerable role in determining the 'best interests' of donor-conceived children. The article concludes by providing suggestions for legislation and policy stemming from the findings, and recommends that greater attention be paid to the voices of donor-conceived children.