I have been following your son’s difficulties and my heart pours out to you.  However, I doubt the treatment has hindered his abilities - just perhaps putting off  surfacing a bit?  My SWCAH daughter who is now 17 months old has spurts of learning.  I would feel like she was not going at the right pace and find out she wasn’t feeling well for some reason (ear infection/meds were off/virul infection etc.) and as soon as we cleared it up and she felt good it seemed like she would pick up and surpass any written expectations overnight.  Being a first time mom, has turned out to be beneficial in this area.  I haven’t expected much and am excited by everything.  In turn, lulls for any reason (especially at these early ages!) don’t concern me.  In the beginning she had so few times she seemed to feel well that I was just happy she was okay!

She is quite small.  She still wears "9-12 mo." clothes and is in a low percentile in both height and weight.  All the people I have talked to have said "proportionate" growth in those two areas is what is important, not the percentage.  I am 5’7" my husband 5’11"  and our families similar except our grandmothers who were both quite short.  She might actually be short by other genes!  (Her endo is not much over 5 feet so I usually don’t concern myself with future size vs. intelligence!)

Put it this way, as a former Kindergarten teacher I can tell you that all kids are better at some things than others and tests only measure certain aspects of what your child knows if anything at all.  If you go by books of what children are supposed to be doing at a certain age then you will always be in turmoil.  My daughter calls both my husband and I "daddy" and, well, she just tried to feed herself for the first time last week.  At the same time she says things like "Patience, daddy, Patience" when her dad has pressed the elevator button twice.    She is smart as a whip in some things and not in others.  The other posts are correct.  I wouldn’t compare and I wouldn’t worry about what you can’t change anyway.  There will always be "what if’s" in every parent’s mind when it comes to this.  Early on, it is so difficult to get the perfect doses so we all wonder, especially as we learn more.  But it really isn’t worth it to look back.  Go with what you know and deal with things as they come. 

Take care, all the best.

RebeccaM