Parents may want to explain that families come in different shapes and sizes, Dr. Gowen says.

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"Bodies come in different shapes and sizes, and the very idea that there is a concrete qualifying number, and if someone can match it they're considered healthy, is wrong, " she says.

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The body harness and head strap had to be as light and unobtrusive as possible too - no mean feat when dogs come in different shapes and sizes, even within breeds.

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