Hey, We’re Talking Percentiles, Not IQs

I’ll have a baby.

Make it supersize.

Like many parents, I have taken personal pride in the high numbers of a child’s percentiles. I mean percentiles on baby-growth charts at the pediatrician’s--not SAT results.

A friend, Adele, is likewise afflicted.

“When the doctor said Scotty was in the 95th percentile,” she says, “I felt like I had gotten a 95 on an exam.”

We think bigger babies are better babies. In terms of science, it makes no sense. Does that deter us?

Parents are competitive. My kid--in particular, my boy--was, let’s say, 8 pounds, 10 ounces at birth. My boy is now in the 90th percentile for height. His weight percentile is the 75th. Isn’t my boy doing well? Isn’t my boy going to be the best?

Of course, a parent might worry if the 90th and 75th percentiles applied to a daughter. (The 90th percentile would mean that only 10% of boys were taller, according to the growth chart.)

Big is associated with robustness, with good appetite, with health. Small is associated with short--bad for boys--and perhaps vaguely with sickness or poor nutrition.

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Naturally, there are going to be a lot of smaller kids. Somebody’s got to be in the lower percentiles.

“It should be a nonissue,” says Morris Wessel of New Haven, Conn., a clinical professor of pediatrics at the Yale School of Medicine, who was in practice for 42 years. (Now he volunteers at a city clinic.) “What’s important is that the child gets on a steady line and stays there.”

It may be a surprise for two tall parents to have a child who is in the lower percentiles, but that ignores the larger gene pool. The pool includes traits of grandparents, aunts, uncles.

Dr. Susan Boulware, a pediatric endocrinologist, sees many children at Yale-New Haven whose parents are concerned about their child’s height, such as “a perfectly normal child who is in the lower percentiles--with the parental caveat, ‘We know we’re small, but we just want to make sure there’s nothing wrong with him or her.’ ”

Although it still seems OK for a girl to be petite, “I think the whole trend is toward [a preference for] taller,” Boulware says. “Parents like to see their babies big. I think in the school-age years, it crosses over to the idea of stronger, bigger, more powerful, more successful.”

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Several years ago, with all the media stories about growth hormones, parents of small children “would ask, ‘Is there anything we can do to make him taller?’ ” Boulware says. Now fewer families ask that question, but she still addresses it, because the question is there, even if unspoken.

Doctors can usually feel comfortable about predicting a normal child’s adult height from charts if growth is following a particular curve but not until the child is 6 or 7, Boulware says. For males, the normal range at full growth is 5-foot-5 and taller. For females, the normal range starts at 5 feet.

“I begin to talk more seriously with families about trying growth hormones when a final height for a boy is predicted to be less than 5 feet, 3 inches; for a girl, about 4 feet, 10 inches,” Boulware says.

Anything between the 5th and the 95th percentile is normal, notes Dr. Annette Lansford, a developmental and behavioral pediatrician at the Carle Clinic in Urbana, Ill. “What’s really most helpful is for a child to have height and growth charted at various office visits . . . You’re looking for a nice, smooth, predictable line.”

Wessel poses this question: Let’s say your husband is 5-foot-10.

“Would he be better if he were 5-feet-11 or 6 feet?”

Often, there is concern about a child’s height when there is no basis for it.