If my son has high functioning autism, is it likely my daughter will have it too?

One one hand...: ...It does run in families, and has a strong genetic component. On the other, the parenting skills you learned in the meantime are very important, and might make a huge difference.

Yes and no: Asperger's and autism may run in some families. But not in all families with one child with the disorder. If it runs in famlies it is likely to be due a multiple factor inheritance not a single gene. In short the only way to tell is to have your daughter tested by a psychologist with expertise in this area.