Hi, my sons are not particularly tall for their age. My son almost 4 is 38" and my other son almost 2 is 31". They are both very healthy, both in the 5th percentile ish for height and 25th ish for weight. What is failure to thrive classed as and is there anything I should look out for that may be stunting their growth? Thanks!
Failure to thrive is when your infant isn't gaining the recommended amount of weight for his age. That issue has nothing to do with height, the concern is that the baby is not getting enough nutrients or the body is having trouble processing the food that he eats.
The pediatrician will start worrying when the child falls below their average percentile or is no longer on the charts. There is not need to worry if they are normally at the 5th or 10th percentiles, just as long as that is being maintained and not going any lower than that. Genetics play a big role with growth so take a look at your family history, and especially YOUR mom and dad's heights. Also, shorter people tend to have shorter kids too.
What's normal ? 
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