There is some evidence that Fetal Alcohol Syndrome can lead to attachment disorders. However, I should say that I don't know a TON about this.... so I don't know if there is research on whether or not these attachment issues show up in FAS babies adopted at birth or not. (If a child is born with FAS and stays with the bfamily, it's likely that the bfamily are not the most responsive, best care caregivers, so it would be hard to tell whether the attachment issues come from the prenatal alcohol exposure, or the poor parenting, or both.)
Generally, I think you don't have to worry too much about this with a newborn. As long as you cut YOURSELF some slack. (The baby may not quite "feel" like "yours" for a while--but obviously you have to keep caretaking and cuddling--and eventually the bond should come. Also, some aparents feel like the baby is theirs from day one, so... this might not even happen to you. Just something to be aware of.)
