Exome sequencing (ES) has revolutionized diagnostic procedures in medical genetics, particularly for developmental diseases. The variety and complexity of the information produced has raised issues regarding its use in a clinical setting. Of particular interest are patients' expectations regarding the information disclosed, the accompaniment provided, and the value patients place on these. To explore these issues in parents of children with developmental disorders and no diagnosis with known etiology, a multidisciplinary group of researchers from social and behavioral sciences and patient organizations conducted a mixed-methodology study (quantitative and qualitative) in two centers of expertise for rare diseases in France. The quantitative study aimed to determine the preferences of 513 parents regarding the disclosure of ES results. It showed that parents wished to have exhaustive information, including variants of unknown significance possibly linked to their child's disorder and secondary findings. This desire for information could be a strategy to maximize the chances of obtaining a diagnosis. The qualitative study aimed to understand the expectations and reactions of 57 parents interviewed just after the return of ES results. In-depth analysis showed that parents had ambivalent feelings about the findings whatever the results returned. The contrasting results from these studies raise questions about the value of the information provided and parents' high expectations regarding the results. The nature of parental expectations has emerged as an important topic in efforts to optimize accompaniment and support for families during the informed decision-making process and after disclosure of the results in an overall context of uncertainty.