Some object to prenatal diagnosis on the basis that it ‘expresses’ a discriminatory attitude towards those with (dis)ability. Namely, the act of screening for genetic information that might demonstrate risk for certain forms of (dis)ability (e.g. developmental (dis)ability associated with Down Syndrome) so that one might then choose to terminate the pregnancy endorses normative assumptions that treat those with (dis)ability negatively or as unequal in moral worth.
It is important in weighing this objection against other considerations to consider the perspective of those who have a screened for or similar genetic trait. Likewise, you might consider how you would feel if any genetic trait that you have were screened for regularly and pregnancies were regularly terminated because of it.
For further reading…
Boardman, FK. (2014). The expressionist objection to prenatal testing: the experiences of families living with genetic disease. Social Science & Med, 107:18-25.
Edwards SD. (2004). Disability, identity and the “expressivist objection”, J Med Ethics, 30(4):418.
Kittay, E. and Carlson, L. (2010) Cognitive Disability and its Challenge to Moral Philosophy, Wiley-Blackwell: Oxford.