Testing a fetus for Huntington’s disease: is the mother’s consent enough?

An interesting divergence between clinical practice and legal requirements appears in the following scenario, which was brought to my attention by a clinician and a genetic counsellor at the Murdoch Institute, Melbourne, last year.

If a pregnant woman asks for a genetic test on her fetus in utero, can the test be lawfully done without the father’s consent? Say, for example, that the mother wants the fetus tested because one of the father’s parents has Huntington’s disease. The father’s risk of inheriting the disease from his affected parent is 1:2 and the child’s risk of having the disease is 1:4; the risk of the father finding out his genetic status from the child’s test is the same as the child’s risk of testing positive, that is, 1:4. If the child tests positive, he or she will develop Huntington’s disease later in life (usually after the age of 40 years). However, a positive test on the fetus also indicates that the father has the mutation and will later develop the condition. This is knowledge that many people do not want to have, and the father may not wish to risk finding out by allowing a test on the fetus. Should a test be permitted if the mother wants it but the father does not agree?