Can amniocentesis detect autism?

No. There is no prenatal test for autism, and any service offering one should be treated with scepticism. Autism is not caused by a single genetic change that can be tested for. It arises from a complex combination of many genetic factors and other influences that are not fully understood, and there is no test — prenatal or otherwise — that can predict it. What amniocentesis can detect is chromosome abnormalities and, where microarray is used, small deletions and duplications. Some of these conditions carry an increased likelihood of developmental differences, including autistic features, among a range of other outcomes. But that is different from testing for autism, and a normal result does not exclude it. This distinction matters because expanded prenatal testing is sometimes marketed in ways that imply more predictive power than exists. If a laboratory or clinic suggests a test can assess your baby's risk of autism, ask exactly which genetic changes are being looked for and what the evidence is that they predict the outcome being described. If you have a family history of autism and want to understand what is known about recurrence, a genetic counsellor is the right person to speak to. They can give you an honest picture — which will be about probability and uncertainty rather than a test result. Anyone can have a child who is autistic. It is not something prenatal testing prevents or predicts.