It is estimated that two to three percent of all pregnancies result in a child with a birth defect, mental retardation and/or genetic disease. Although many of these problems are obvious at birth, some become evident later in childhood or in adulthood.

Some common reasons for a referral to medical genetic services include:

• A typical genetic evaluation starts by meeting with a counselor to discuss the reason for referral, the patient and family's concerns, as well as relevant family and medical history. Subsequently a medical geneticist performs an examination followed by a discussion between the genetics team and the family about the possible diagnosis and recommended tests and referrals.
  
  
• The evaluation and diagnosis will also include a prognosis and other discussions about heredity and reproductive options

• Children or adults with birth defects such as cleft lip / cleft palate, congenital heart defects or other physical malformations.
  
  
• People with unexplained mental retardation, developmental delay or growth problems.
  
  
• Individuals with known or suspected genetic conditions such as muscular dystrophy, sickle-cell anemia or Down syndrome.

• Pregnant women and women planning a pregnancy, who are in their mid-thirties and older.
  
  
• Pregnant women with abnormal screening tests or ultrasound results.
  
  
• Women who have been exposed to certain drugs or medications during pregnancy.
  
  
• Women with medical conditions such as diabetes, seizure disorders or lupus.
  
  
• Individuals in ethnic groups that have a higher risk of certain genetic diseases, such as Tay-Sachs disease, sickle-cell anemia, thalassemia and cystic fibrosis.