This article reports on a study of individuals and couples who provided or received embryos under the Snowflakes® embryo adoption programme in the US and had established contact with each other. This mixed-methods study comprised two phases: an online survey, followed by email interviews. It explores participants’ initial experiences of establishing contact after embryo adoption and the birth of a child; how they developed and negotiated boundaries in their relationships with their respective provider or recipient families; and the fluid meaning and role of genetics in forming the basis for relationships. To our knowledge, this is the first study to explore how relationships are negotiated in these emerging family forms. This article extends knowledge and understanding of embryo adoption and contributes to the growing body of sociological research on information exchange and contact between parents who have children who share the same embryo or gamete donor.