M’s nine-month check up was Monday. She measured in as follows: 20 lbs., 6 ounces, 75th percentile 26.5 inches, 25th percentile 90th percentile on head size Still need to get the girl to lengthen out.  The pediatrician I share a mortgage with tells me you can estimate a person’s adult height by doubling their height when they are two.  So not…