At the booking clinic you will ask about conditions in the family. Sometimes, a known condition will confirm a mode of inheritance (such as cystic fibrosis). In other cases, the pattern of people with the condition may indicate the need for referral to determine if there is a strong genetic component.

Clinical clues suggesting that a condition has a strong genetic component include the following:

• An individual or a couple with three or more pregnancy losses (miscarriages or stillbirths)
• Multiple congenital anomalies or dysmorphic features, particularly if associated with developmental delay
• Multiple closely-related individuals with the same condition, particularly if the condition is rare
• Medical problems in the offspring of parents who are related by blood
• Disorders which occur at an earlier age than usual (especially if onset is early in multiple family members)
• Congenital or juvenile deafness
• Congenital or juvenile blindness
• Sudden cardiac deaths in people who seemed healthy