confusing height calculations

[Guest guest]

My son is 3 yrs. old, 26.5 lbs., and is 35 in. tall. When our

pediatrician plots his height on the computer, it comes out just

below 15th percentile (does this sound right?). However, we just got

Jack's write-up from the geneticist, and she has him down as just

below 5th percentile (and he definitely measured 35 in. in her

office)! Very confusing. Anywhere to do the calculations on the

Internet? Thanks!

Marcy