Yes, I know that we're a little past Thanksgiving now, but I wrote this on the morning of Thanksgiving and am just now "getting around" to posting it :).
Dear Son or Daughter,
I learned just this morning that God is blessing us by bringing you into our lives. I can't tell you how excited and grateful your Dad and I are (and Eli and Layla, too, though they don't quite realize what's going on yet). You are already such a blessing to us and we can't wait to meet you! Happy Thanksgiving and welcome to our family.