 In the context of prenatal testing, as with assessments of adult functioning, the extent to which a disabling condition reduces well-being depends on the conception of well-being that is adopted. With prenatal testing, however, there is an additional complication: there is massive uncertainty about how the detected variants will be expressed in the developing child. That depends on their their interplay with other genes and interaction with a variety of environments. The formidable challenges of predicting phenotype may be more readily acknowledged by health professionals than the even more daunting challenges in the non-medical assessment of how life with a given phenotype could go for the person living it.