
remember, there are averages and then of course, there are kids who are above or below these averages.
Toddlers are just like adults...some adults are naturally slimmer than others, and some are bigger, and some are average.
http://www.babybag.com/articles/htwt_av.htm
My son was 27 pounds ate his year checkup. A bit above average. Your sons height is right on target for his age, so his is growing, and therefore seems to be healthy!
Think about it...