does this seem too small for his age?

my son hardly eats on certain days and he seems too little to me, I am constantly worrying about him.He  weighs 27 lbs. and 33.5 inches tall and he is 30 months old.

[Renee Radenberg]

His weight is just below the 25th percentile and his height is just below the 5th percentile for his age. Genetics may be a factor in his stature. Are there males in the family with small stature? Based on his weight / age, he should be consuming approximately 1600 calories per day as recommended the following; Fruits (limit fruit juices) = 1.5 cups; Vegetables 2 cups; Grains (cereals, breads) = 5oz equivalents; Meat & beans = 5oz equivalents; Dairy products (milk, yogurt) = 3 cups; Oils = 5 tsp; Additional calories to be used discretionary = 132. This food needs to be divided up between 3 meals and snacks between meals daily. Make sure he is eating a protein food each meal (meat, cheese, or yogurt) and try milkshakes instead of milk to help give him additional calories and protein for growth.