Is fetal alcohol syndrome hereditary or is there a hereditary disposition associated with getting it?

Acquired. Fetal Alcohol syndrom is acquired during a pregnancy related to maternal alcohol ingestion and inadequate diet. .
Sort of. Addiction in general may be influenced by heredity, so a child who is born to a mother with alcoholism has an increased risk of also developing problems with addiction. However, if the mother with alcoholism doesn't drink alcohol during her pregnancy, then her baby will not have fetal alcohol syndrome (fas). Fas is completely preventable by not drinking alcohol while pregnant.
Varies with ETOH. Fas involves actual interferance with growing cells of any fetus by the toxic breakdown products of alcohol. The more you drink at any point the more cells you can injure. The interplay between learned behavior & inheritance in etoh abuse is complex.It does not change the facts; the more you drink during pregnancy, the more likely you will damage baby. No level has been found safe.