It Can Be Hereditary
Anxiety can be passed down through family genetics, and many who suffer from this condition may have had a family history of anxiety and related disorders. Biological factors contributing to anxiety is an emerging field of study at this point and more will be discovered in the next ten to fifteen years. If both parents suffer from a clinical anxiety disorder, their child will have a higher chance of developing it.
However, this type of occurrence may not be biological; it may be environmental or psychological due to the conditions in which the child was raised (with two parents both suffering from anxiety disorders). Many researchers and medical professionals will agree anxiety is a combination of several factors including biological, environmental, and psychological. This opinion is the consensus, although many doctors will ask if there is a family history of mental illnesses if visiting for a first appointment.