My kid was an outlier because my genetics tend to being tall and thin. If he was being measured against a set of healthy people with similar genetics he would not be considered an outlier - but this calculus is not considered when he is measured and judged aberrant. Our doctor being Indian was able to see from her experience that he was "normal" - for a kid with an Indian parent. Another doctor (like all the ones I grew up with) might not have the same insight and conclude there is a problem.