Abstract. This article examines how expanded carrier screening (ECS) – a genomic test based on whole-genome sequencing – has been integrated into Spain's assisted reproductive technology sector. Marketed as a tool to enhance reproductive safety and personalization, ECS has become increasingly routinized within third-party gamete in vitro fertilization (IVF) through its use in genetic matching (GM), a technique that identifies shared genetic risks between donors and recipients.

Drawing on qualitative data—including regulatory documents, professional guidelines, fertility clinic websites, and interviews with clinical experts—this study offers an analysis of how ECS has been localized, legitimized, and routinized in Spain's ART sector. The central role of private actors in self-regulating ECS, similar to other innovative “add-ons”, has deepened the gap between public and private ART, the socio-economic stratification of the access to fertility services and further commercialized an already market-driven sector.
Unlike other non-genetic add-ons, ECS-GM targets the pursuit of “healthy babies,” reshaping the responsibilities and expectations of clinics, recipients, and donors, and contributing to new forms of anticipatory care. Conceptualized through the lens of a “matching economy,” ECS-GM fuses donor anonymity with personalized selection by shifting the recipients’ choice from donor identity to selection techniques, taking an active role in what we name an “asymmetrical gamete matching economy.”

This study contributes to critical debates on reproductive governance, marketization of genomic testing, and ethical politics of emerging biotechnologies, illustrating that reproductive technologies are embedded in institutional negotiations and molded by culturally and legally situated practices.