Final answer:
Chorionic villus sampling can be performed earlier in pregnancy than amniocentesis, allowing for earlier genetic testing and decision-making.
Step-by-step explanation:
An advantage that chorionic villus sampling has over amniocentesis as a method of prenatal testing for genetic disorders is that chorionic villus sampling can be done earlier in pregnancy. This allows for earlier detection and decision-making regarding the pregnancy. Unlike amniocentesis, which is typically performed between the 15th and 20th weeks of pregnancy, chorionic villus sampling can be performed as early as the 10th week. This means that results from chorionic villus sampling are available sooner than those from amniocentesis, giving parents more time for further testing or to make important decisions.