I had the exact same concerns.  My daughters were 8 and 6 when my son was born.  He is the only one with CAH and presents as a simple virilizer.  Our endo. at the time told us the same thing yours did.  My daughter started puberty right after her ninth birthday and she is extremely tall (always has been off the charts).  I again became concerned so we had them both tested.  Both of my daughters tested as carriers only.  My nine year old tested in the "high" carrier range but it was still below the "affected" range on the nomogram.  I have seen several posts from carriers that have some "symptoms".  I think my daughter may be one of these.  She has started getting regular headaches in the afternoon and my gut tells me this is related.  At my sons next endo. appt (in early August) I am going to talk to him about this and see if he wants to do a bone age just to make sure everything is ok. 

My husband and I are not carriers for the same type of CAH.  My husband carries the salt wasting gene and I have the simple virilizing gene.  We had DNA testing done on ourselves and on our son.  Therefore my son has one of each.  Typically (from what I was told) the offspring’s Phenotype (the way their symptoms present) will follow the less severe gene.  Maybe this is where the possiblity of having children with different versions of CAH lies.  I wonder if one parent was a carrier for late onset and another for Salt waster if there would be more of a possibility of having one child with salt wasting and another with late onset.

I’m sorry my information is not scientific just the way I have interepreted information given to me from many different sources in my own search for answers.

If your daughters are not exhibiting signs of early puberty then most likely everything is a-ok.

Lisa R.