Month 6 Worry: How Tall Will My Child Be?

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As your baby hits the 6-month mark, your curiosity may pique about how tall she may be someday. Our pediatrician shows you how to make a calculated height guess.

Parenthood really begins as we have this little being handed over to us after delivery. Who does the baby look like? Is that Papa Bob's nose? Aunt Audrey's chin? It is all a great mystery, and unless we have a forensic artist in the family to draw us the future, it's natural to wonder what this little body will become.

What's the Issue?

One of the most common questions asked in my practice is, "How tall will my baby grow up to be?" This is a question that can be answered with some certainty by looking at genetic potential—that is, how tall the biologic parents are. Your pediatrician can calculate this (called a mid-parental height), and you can figure it out at home, too.

Consider the Numbers

The mean height in America is about 5' 9½" for men and 5' 4½" for women. Our genetic programming aims us at a point on the bell curve, and other factors create error or variability to either side of that prediction. Dad is 6' tall? Well he's close to the 90th percentile for adult men, meaning he's taller than about 90 percent of the population. A mere 2½ inches on either side of average encompasses 80 percent of the American adult male population. It is interesting how homogeneous we all are, when you think about it. Click here to visit the Centers for Disease Control (CDC) growth curve charts.

What Parents Can Do

To calculate your son's genetic potential, take Mom's height plus 5 inches and add Dad's height. Now average the two. For example, if Dad is 5' 10" and Mom is 5' 3" you would take 5' 10" and 5' 3" plus 5" (or 5' 8") and divide that answer by two. The average of 5' 10" and 5' 8" is 5' 9". That is your son's genetic potential.

So:

(Mom's height + 5 inches) + Dad's height = Son's genetic growth potential
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To calculate your daughter's genetic potential, take Dad's height minus 5 inches and add Mom's height. Now average the two. For example, if Dad is 6' and Mom is 5' 2" you would take 6' minus 5" (or 5' 7") plus 5' 2" and divide that answer in half. The average of 5' 7" and 5' 2" is 5' 4½ inches. This would be your daughter's genetic potential.

So:

(Dad's height - 5 inches) + Mom's height = Daughter's genetic growth potential
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If the math is tripping you up in feet and inches, these calculations may be easier if you convert all the heights to inches first.

(Does your baby have an older sibling? Click here to use an interactive Height Predictor tool.)