Look in mirror to see how tall your child may be

The young boy had been a patient in our group practice for a couple of years, but it was my first time meeting the family.

As usual, I started the well child visit with a review of height and weight percentiles and a look at the standard growth chart.

The boy wasn't particularly big, which seemed to bother the parents, but he was healthy and energetic and loved playing all sports - especially basketball.

"Will shooting hoops make him grow taller?" his mom asked, hopefully.

She didn't say it, but I could see visions of Bull's big men Joakim Noah and Pau Gasol dancing in her head.

I tried to put a positive spin on my response while remaining medically accurate, and answered, "Well, being physically active and eating well will allow him to grow to his genetic potential."

Then I let her down gently as I pointed out that based on parental stature, the boy was likely to reach about 5'9" - a perfectly acceptable adult height.

The mother looked stricken and blurted out, "But he's got to be tall to play sports!"

A few replies came to mind, including, "Not my fault, ma'am. I wasn't the one who told you to have children with this guy." And, "We can't fix this (perceived) problem, 'cause you can't fight genetics."

And finally, "Don't sweat it mom. The reality is that only about 3 percent of high school athletes will play college basketball anyway, and only about 1 percent of these rare college players will go on to be drafted by the NBA."

Of course, I said none of these things. Instead, I quickly changed focus after noting that the boy was growing very well and was likely to end up right around the average height for an adult American male.

In his article in Pediatrics in Review, Dr. Benjamin Weintraub explains that a child's genetic growth potential can be estimated through a simple calculation of mid-parental height.

For a girl's height estimate, five inches are subtracted from dad's height and this adjusted paternal height is then added to mom's height and divided by two.

To arrive at a boy's height estimate, five inches are added to mom's height and this adjusted maternal height is then added to dad's height and divided by two. The predicted height range for each gender is expected to be within three inches plus/minus of this calculated mid-parental height.

Weintraub notes that the childhood growth process is influenced by maternal nutrition and uterine size, inheritance of parental height, nutritional status of the child, and the important "interplay" of a variety of hormones.

Size at birth is more dependent on maternal factors and the "in utero" environment, and generally does not predict an individual child's growth potential. The pediatric researcher finds that it is common for children to "shift" toward their genetic growth potential between the ages of six and 18 months.

Little babies of tall parents often start their "catch-up" growth around six months of age, while big babies of small parents tend to decelerate in growth at about 12 to 18 months of life.

• Dr. Helen Minciotti is a mother of five and a pediatrician with a practice in Schaumburg. She formerly chaired the Department of Pediatrics at Northwest Community Hospital in Arlington Heights.