My baby is 3 weeks throwing up every time she eats . her dad was alcoholic could this be fetal alcohol syndrome i'm concerned ?

Not usually a sign: Fetal alcohol syndrome, FAS, can cause some problems in the head and neck but I am not aware of it causing problems like you describe The baby is likely having normal reflux which is seen in almost all babies. This can be helped with smaller and more frequent feedings. If the baby does not gain weight then your doctor may start a treatment but generally babies outgrow the vomiting/reflux