The most potent risk factor in the development of Fragile X syndrome is presence of Fragile X syndrome in any of family members. Other risk factors include family history of developmental delays, autism or intellectual deficit of unknown origin and infertility in the family.

Common risk factors in the development of Fragile X syndrome include family history of Fragile X syndrome, mental retardation or autism of unknown origin and developmental delays in the family members. Family history of infertility associated with elevated FSH levels or premature ovarian family have shown some linkage with Fragile X syndrome.