Since 2002, a parental project involving assisted procreation in a private context has been a possible and recognized in Quebec. A lesbian couple can thus proceed outside the medical system by receiving a sperm donation from a man who agrees to act as a donor, without being legally recognized as a father. In such a context, telling children the identity of the man involved in conceiving them raises particular challenges. This article presents qualitative data obtained from a longitudinal study of fourteen Quebec families, ten of lesbian mothers and four of donors, on this turning point in their family trajectories. The results show that the adults involved deploy different disclosure strategies, which vary in proactivity. They must also agree on the information to be conveyed and deal with the relational issues raised by the disclosure. The children’s understanding of their biological relationship with the donor does not seem, from the point of view of the adults involved, to create any particular expectations. The children show a certain curiosity, but this does not come with the imperatives of a more sustained involvement of the donor in their lives.