Genetic counseling for patients with birth defects.

Genetic counseling for birth defects is complex because of the etiologic and pathogenetic heterogeneity that exists. It is necessary to arrive at as precise a diagnosis as possible by evaluating gestational history for environmental factors, family history for genetic factors, and patient anatomy for clues to embryologic mechanisms. Recurrence risk counseling is based on a combination of theoretic risk assessment and empiric data. Genetic counseling may be a difficult and stressful task because of the imprecision in these data and the uncertainty inherent in interpreting them. Health professionals engaged in this activity should educate patients and families about the assumptions involved and the limitations of such estimates.