Understanding Your Child's Growth: An Interview with Dr. Mitch Geffner

Children's growth patterns and rates can often be a source of anxiety for parents. To alleviate concerns and provide insights, we turned to an expert in the field, Dr. Mitch Geffner, a member of World-Class Scientific Advisory Board and a revered pediatric endocrinologist and professor at Keck University. He recently featured on the Ask Dr. Jessica podcast, providing in-depth knowledge on the topics of pediatric height, growth, puberty, and more.

Pediatric endocrinologists, as Dr. Geffner explains, are specialists who study hormones in the body and their impact on various systems. The patients they generally deal with can be summarized by the conditions "too tall, too short, too big, too thin, too sweet, not sweet enough, too salty, not salty enough". These simplistic categories translate into more complex situations such as children not growing as they should, children growing too much, children with weight issues potentially leading to type two diabetes, thyroid problems, puberty issues, and adrenal problems.

What Impacts Growth

Dr. Geffner's primary areas of interest lie in conditions that affect growth and puberty, and specific conditions that impact the adrenal gland. One of the key questions parents often ask is, what is the 'normal' growth that they should expect to see from their children?

The concept of 'normal growth' depends on various factors such as the child's age, sex, overall health, and whether or not puberty is present. As a general rule, boys or girls aged between four and ten years should grow an average of two inches per year. Where a child falls on the growth chart isn't necessarily indicative of a medical problem, as long as they're growing at the normal rate. However, a drastic change in a child's growth rate can be a red flag for potential health issues. This is why growth rate, or velocity, is crucial and requires a minimum of two measurements over at least a six-month period.

Another crucial factor in determining a child's potential height is the height of their parents. This is due to the significant influence of genetics on a child's growth. Children of taller parents are typically taller, and children of shorter parents are typically shorter. However, these genetics can be overridden if the child experiences a severe chronic illness such as heart disease or any condition that significantly impacts their nutrition.

Therefore, understanding a child's growth is not a simple task. It involves taking into account multiple variables including their age, sex, overall health status, presence of puberty, their parents' height, and whether they are experiencing any serious health conditions. To ensure your child is growing adequately, parents are encouraged to consult a pediatric endocrinologist like Dr. Mitch Geffner, who can provide expert advice based on an individual child's circumstances.

Try out Growth Calculator here

Nutrition is Key to Helping kids reach their full height

Dr. Mitch Geffner emphasizes that nutrition, primarily in the form of adequate caloric intake, plays an essential role in a child's growth. The basic premise is that a child who gains weight appropriately will likely grow at a rate that aligns with their genetics. While severe malnutrition can drastically affect growth, especially in third-world countries, in developed nations like the United States, it's typically less of an issue.

If a child has poor calorie intake, Dr. Geffner recommends supplementing it with high-calorie, nutritious shakes or meals. However, he clarifies that boosting nutrition won't transform a child's height percentile dramatically – for example, from the 5th to the 95th percentile.

Read the Full Transcript:

Dr. Jessica

Hi, and welcome to this week's episode of Ask Dr. Jessica. I'm really thrilled to have one of my favorite pediatric endocrinologists here, Dr. Mitch Geffner. He's a professor at the Keck University. I've known Dr. Geffner a long time, and I'm thrilled to have you here to ask you all the questions we have about pediatric height, growth, puberty, all the good stuff. 

Dr. Mitch Geffner
Thrilled to be here, Jessica. 

Dr. Jessica 

So for people that are listening and they don't know what an endocrinologist is, you describe what a pediatric endocrinologist is and what kind of cases that you see and what particular diseases you guys study. 

Dr. Mitch Geffner
Sure. Well, the basic premise of pediatric endocrinology is around hormones, which are chemicals, if you will, in the body that regulate many systems. And I often answer that question to lay people with the kinds of patients that we take care of are too tall, too short, too big, too thin, too sweet, not sweet enough, too salty, not salty enough. As a simplistic sort of way to capture the kinds of things we do, what does that really mean?

Well, we see children relevant today's discussion who are not growing as they should. In some cases, we see children that are growing too much. We see, unfortunately, a lot of children that are overweight, which often leads toward, or mainly toward type two diabetes in children. We see thyroid problems, puberty problems with the ovaries and the testicles not working, which, of course, is partly related to puberty, but other things, adrenal problems. 

Dr. Mitch Geffner
The list is not that long, but it keeps us busy. 

Dr. Jessica

Just out of curiosity, within all of those issues, do you have a favorite or a particular area of interest? 

Dr. Mitch Geffner
I think that is actually why I'm here today. But certainly conditions that affect growth and puberty are big for me, and I'm also involved with some conditions that affect the adrenal gland that are kind of rare. 

Dr. Jessica

So then let's start with your favorite topic, or let's start with one of your favorite areas of interest. Growth. Certainly a question I get a lot as a general pediatrician, can you talk about what's a typical or normal expected, what's normal growth that we should expect to see from children? 

Dr. Mitch Geffner
Well, that sounds like a simple question, but it's not. So it depends on a few things. It depends on the age of the child. It depends on, to some extent, whether it's a boy or girl. It depends on the health of the child. It depends on if puberty is present.

Sort of all of those factors go into it. And as a general rule, whether you're a boy or a girl, if your age is between four and ten years, you should grow, on average, two inches per year. That's what I teach to trainees. That's what I teach to parents and families. And it almost doesn't matter if you're growing that amount, what part of the chart you're on when I say it doesn't matter. Of course it matters to the family, but it doesn't matter in the sense that you're likely to find a medical problem to account for that. 

Dr. Mitch Geffner
If that child is growing on a line or a percentile line that is lower than it should be based on the family high genetics, or if it's just on a line that the parents of the child don't like, whether or not it's correct or not for the family high genetics. But that two inches per year. Between four and ten is a single number. I mean, there's some kids, taller kids from taller parents will grow more than that. Kids born to shorter parents will grow somewhat less to that.

Maybe a quarter of an inch on either side, but not dramatically. So that's the sort of bar to compare what an individual child's growth chart looks like. And I don't see patients unless the growth chart arrives before them, maybe at the same time. But the worst thing for me and the worst thing for the visits is if it comes after, because I will have measurements the day they come, but I won't know how that child got there. 

Dr. Mitch Geffner
And so I need to see the path, the trajectory. A child that is growing at that normal rate will never have anything wrong, almost even no matter what part of the chart they're on. A child who's growing slowly over, let's say, a six or twelve month period could have something wrong. And it doesn't matter what that height is, because you could be at the 95th percentile really tall.

But if you drop down to the 50th percentile over a year, you're not short by societal standards, but something happened that made you do that. So you could actually have, in that setting, a serious medical problem. And so the rate of growth is the key. And to have a rate or velocity, you have to have at least two points over a reasonable period of time, which for me is six months. Maybe I'll settle for four, but six is ideal. 

Dr. Mitch Geffner
So that's sort of the way I look at it. And I also look at this in the context of the parents heights. I've alluded to that, and I will tell you that when the patient is referred to me, the parents heights come along ahead of time with, let's say, the information that comes from the doctor's office maybe 25% of the time.

So for the pediatricians who are parents in the audience, please send that information. It's inexpensive, it doesn't hurt, it's not a blood test. And it's so important, and if you don't send it, we get it. But it makes it just easier before I walk in the room to know what to expect. 

Dr. Jessica

Okay, now this may be a leading question, but why is it so important? Do you find that parents height makes a big difference when you determine the potential height of their children? 

Dr. Mitch Geffner
Absolutely. There's two key things that sort of control height. One is genetics. So taller parents will typically have taller children and smaller parents will typically have smaller children. Less important are the grandparents and the aunts and uncles, but it's really the parents. Now, if the parent is somehow shorter than, let's say, a sibling that parent has of the same sex, and maybe that parent had a medical condition at affected height, the formula doesn't work quite as well.

And that gets to the point of the other thing that can alter expected height, and that's a serious chronic medical illness, let's say severe heart disease, things of that nature. So your genetics, unfortunately, you may not get the full benefit from them if you as a child have some serious medical problem that affects your nutrition or just anything that's important in the world of growth. 

Dr. Jessica

A lot of parents will say to me, they'll say, well, I have a really tall grandparent or a really tall uncle. Does that play much predictive value in height of a child? 

Dr. Mitch Geffner
Minimally. And I hear that too. 

Dr. Jessica

Is there a way that parents can predict the height of their child based on the mother and the father's height? 

Dr. Mitch Geffner
Right? Well, yes, there's something called the Internet, and you can look it up, but there's probably more than one formula. But the formula that we use that works sort of the best, I'll tell it to you. It depends if you're making a prediction for a boy or for a girl, obviously. So if you wanted to know for a male child how tall they're supposed to be, using solely the parental heights, which is what we do, you average the father's height, as is inches with the mother's height.

After you adjust her height by five inches, that masculinizes her. That would have been the height she would have been had she been a male. So if a mom's five two, she becomes five seven for this equation. And let's say the dad is 6ft. So 6ft average was five seven is five nine and a half. And so you have to use that correction factor. 

Dr. Mitch Geffner
Now, nobody, including me, certainly can predict height to a single number. That would be I wouldn't be on this podcast. I'd be working in Las Vegas at a lounge show, making money. But seriously. So we use a statistical sort of method to broaden that range by plus or minus two inches on either side.

And that's about 70% accurate. It's still not 100% accurate for a girl. It's sort of the reverse. You use the mother's height as is because she's a girl, and you feminize the father's height by subtracting five inches because that's what he would have been had he been a female. And then you do the average in plus or minus two inches. That's the formula. 

Dr. Jessica

And this gives you a rough idea what to expect for your child's future height. 

Dr. Mitch Geffner
70% roughness. That's pretty good. 

Speaker 1
That is pretty good. Now what about there's a lot of questions I get from parents that they want to know what multivitamin to give their child. They're concerned that their kid's not eating enough. How much do these factors make a difference in determining final height? 

Dr. Mitch Geffner
So I think the broader question is what is the role of nutrition in all of this? And clearly nutrition is important. It boils down mostly to calories. The reality is, if a child gains weight reasonably well, that child will grow to the rate that he or she is supposed to. Now, in a third world country where calories and protein intake can be severely limited, different story.

But in the United States, that's less of an issue. But if a child is having a poor calorie intake for whatever reason, supplementing that is not a bad idea. Whether that's with prefab sort of high calorie formulas, formula shakes, or going to a store or making your own shakes, with a lot of calories and good nutrition, it probably doesn't matter greatly whatever is palatable. So that's okay. But that's not going to take a child whose height is at the fifth percentile and bring it up to the 95th percentile. 

Dr. Mitch Geffner
It's not going to happen. Okay, that may help a little bit. Things such as vitamins, like vitamin D in particular, these are all good for your health. I'm all for them as long as too much of them is not taken, because actually people don't sometimes realize that you can get very sick from excess intake of vitamins. Whether any of that is going to cure, if you will, a growth problem in general, I would say it doesn't. 

Dr. Jessica

So if a parent says to me, dr. Hockman, my child is too short for my liking, I want to make sure they grow to their full potential, I want them to grow more. Is there anything a parent can do for their child, whether it be sleep more, offer certain nutrition or supplements? I just want to hear what your thoughts are. Is there anything at all we can tell parents to do? 

Dr. Mitch Geffner
Well, as I kind of stated about the nutrition angle, unless somebody is severely undernourished, that's probably going to not greatly affect the height, may replenish some things that are missing, perhaps, or at low levels, but it's probably not going to have a dramatic effect on height. As to sleep, I get that asked that one. Also, I think we're all brought up, our parents tell us, oh, if you'll sleep more, you'll grow more. And that's based on well, it's based a little bit on the science of growth hormone.

The body's growth hormone is produced mostly when we sleep. And so the parent, in a way, assumes that, well, less sleep, less growth hormone. Simple. But there's never been a study done that. I'm aware of a research study that has shown a difference in height based on hours of sleep. So one of the other reasons parents want their kids to get more sleep is so they have a little more time without their kids to recover from the day. 

Dr. Mitch Geffner
But that's I'm guilty of that whole nother thing. 

Dr. Jessica

All right, so I think that's good to hear. I think for some parents, maybe it'll relieve the stress that there isn't more for them to do, that they don't have to get their kids boost or insure or get them to bed at 07:00 to get them to be an inch or two taller. 

Dr. Mitch Geffner
That's a good summary of what I was saying. 

Dr. Jessica

So is there a time, though, when parents should pay attention if their child is not growing enough, when they should see a pediatric endocrinologist or talk to a pediatrician? What are the warning signs or lack of growth per se? Is it when they're not growing those two inches a year? Is there anything else that parents should be paying attention to? 

Dr. Mitch Geffner
Well, I mean, the cardinal thing that both the parents and the pediatrician or primary care physician should be looking at is what has happened, like over the previous year. Kids come in for physicals typically once a year, and so there's numbers that should be gauged. I know kids will come in between those annual physicals, but oftentimes height is not part of an acute care visit, so you may not get that information.

But if there's a beginning of a trend, but it's a relatively small trend, then maybe the pediatrician should see the patient back in four months or six months, not wait another year specifically for the purpose of a height check. But the old sort of standard, if a child's height over a reasonable period of time, say six to twelve months, crosses over one of those sort of prefab lines, those percentile lines on there, certainly if they cross two immediately, that child should be evaluated by an endocrinologist. 

Dr. Mitch Geffner
But I should point out to you, and this probably makes up the bulk of my business, and that is parents still sometimes infrequently want their child's growth fixed, even if it's not broken. And what do I mean by that not broken? That meaning there's not an underlying medical condition. They're just small and having a tough time, say at school. Maybe they're getting picked on.

Unfortunately, bullying is ever prevalent. Sometimes they have a younger sibling who's past them in height. That actually worries parents. And it's tough on that kid because the younger one sometimes says, I'm taller than you are. Whatever. And so the psychosocial ramifications of being small in my eyes are large. Maybe not in an insurance company's eyes, but in mine they are. And so I see plenty of patients who are not falling off, but they're just small and smaller than they should be. 

Dr. Mitch Geffner
Now, some of those when we didn't get into yet to the concept of the bone age, which is I think we need to get into that some of those children are just going to be late bloomers and their final adult height. They'll just get to it after their peers do their final heights and they'll turn out just fine.

Unfortunately though, they'll be at a disadvantage throughout their childhood because they'll be small and that could affect them socially, it could affect them athletically. It's another reason parents come. My child is a great basketball player, but he's too small. I'm sure you see those too. 

Dr. Jessica

Would you say that the late bloomer phenomenon is probably the most common reason why kids are shorter than their predicted height from parents, or not necessarily at. 

Dr. Mitch Geffner
The moment that I see them? Yes, absolutely. 100% yes. Okay. Probably the most common reason I see a referral though, is because a child is short and the parents are short. That's not a late bloomer, that's just what we call genetic short stature or familial short stature. Both of those entities are variations of normal, but sometimes variations of normal from which the child suffers. And secondarily, then the parents feel bad, want to try to help their child.

And I see many more patients with those two situations. I don't even want to call them conditions because they're not conditions, they're just variations of normal than I do of children with something that's a real disease causing their short stature. Disease is very rare in the growth field. Definitely it happens, and it's going to happen more in my practice than it will in yours because patients are funneled to me like that. 

Dr. Mitch Geffner
But still the majority of the patients I see, they're otherwise healthy. They're just slow growers for either familial reasons or late blooming reasons. 

Dr. Jessica

Right. In my personal life myself, I'm almost five nine, my husband is six one, and our son is the 15th percentile for height. And so I monitor that he does grow that appropriate two inches every year. It is what it is. It'll be what it'll be. But I'm curious to see if he'll be a late bloomer. Well, maybe at some point I'll do the Bone Age, if you want to. 

Dr. Mitch Geffner
That's a great segue. And I'm going to whisper to you should get the Bone Age. You don't have to. So what's a bone age? Bone Age is the age of the bones. And how is a bone age determined? It's determined simply from looking at the configuration, presence and configuration of growth plates on an X ray of the left hand. And people always say the left hand, where does that come from?

And so 50 plus years ago, when the concept of Bone Age was first sort of discovered, the standards were taken using left hands because it was thought that since most people are right handed, you should use the nondominant hand. It turns out it doesn't matter. But the book which we use to sort of determine the Bone Age is a book of left hands. Now the Bone Age should normally be the same age as the child. 

Dr. Mitch Geffner
So if you were five years old, you should have a five year old looking hand. If you were ten years old, you should have a ten year old looking hand. Now, if per chance, let's say the child is ten and they're the size of an eight year old, they may well have the bone structure, the bone age of an eight year old. And so meaning that it's two years younger than they actually are.

If that's the case, they're going to be two years shorter than they should be at that moment. But they should have the ability in the future to grow for two extra years after the age when their peers of the same age stop growing, to then catch up. So it helps them in the future. If you can see into the future, it's a good thing and you don't have to do anything about it because it's going to happen by itself. 

Dr. Mitch Geffner
But some people are impatient or some people want the quick fix, so we have to sort of deal with that as it comes up. Now also, when your bone age is two years later than you are not infrequently going to the past, you will find that child's teeth were late. Either eruption of the first baby tooth instead of being at six months, let's say it's at a year, or instead of the loss of the first baby tooth naturally, which typically is around the age of six, happens at seven or eight.

And then the parents go, what's going on here? What's taking so long? The kid says, all my friends are getting their money for losing their teeth and I'm poor. Sometimes parents don't remember if they have a bunch of kids. It's hard to remember these things, but it actually can be sort of an early clue that what the future is going to hold in the world of growth. 

Dr. Mitch Geffner
And also, lastly, if your bone age is two years younger, let's in that example of ten, it's eight. So let's say when you're, I don't know, twelve, it's going to be ten, and you're not going to start puberty when your friends do either. You're going to start puberty late because the timing of the onset of puberty is much more closely linked to the age of the bones than to the age of the child, if the two are significantly different from one another.

So that sometimes adds insult to injury because you're going to high school 9th grade, and you're a small boy and all the girls have already had their growth spurts and we haven't even talked about that yet. But sometimes the perception and understandably of where you fit in, which is often gauged on size, becomes even more awkward when you go to a new school, especially when there's older kids than the seniors who are giants, relatively speaking. 

Dr. Mitch Geffner
So this can be hard, we just need to be sympathetic to it. 

Dr. Jessica

I notice the parents that seem the most concerned. I find, not to generalize, but I meet a lot of fathers who are concerned when their sons in particular are shorter. And I think when I ask them more questions, they remember their childhoods when they were shorter and they worry for their children. They want them to have an easier childhood. So I do find that the late bloomer phenomenon tends to be genetic. Would you agree with that? 

Dr. Mitch Geffner
About 50% of the time, half interesting, the other half not. But it'll be possibly passed down to the next generation. 

Dr. Jessica

So let's say, for example, my son, if his bone age, I find, is two years behind, is there anything else that I should do? Or can we call it a day and say, oh, okay, I know my son's going to be that late bloomer and he'll be delayed a couple of years and eventually he'll grow enough? Or do you think, as an endocrinologist, from your perspective, is there any more testing that should be done? 

Dr. Mitch Geffner
Not if he's consistently growing at a normal rate at that setting with that bone age reading, no, that's really just reassurance for me to you. That's a freebie now, that's really great. 

Dr. Jessica

To know because a lot of parents will find the bone age is delayed. And there's a question should we be checking more hormones just to make sure? But good growth. 

Dr. Mitch Geffner
Totally agree with that. So that's why you need accurate height measurements over time. That's the guidepost for that. And I should just qualify. We're probably talking about after the age of two years because there's another thing that happens sometimes that confuses the matter. So if we go back to birth for a second, the birth measurements, certainly birth weight doesn't correspond with anything because if a mother is well, nourished, she's going to have a big baby.

Sometimes you see growth deceleration after birth both in weight and length because the mother was just too good of a self feeder and maybe she put on a little too much weight. And so that makes the baby grow bigger and actually outdo its genetics in fetal life. And so when the baby comes out, they channel down. We always talk about growth that sort of channels up, but you can see channeling down of growth. 

Dr. Mitch Geffner
And so in that window, I think, one unless there's some other medical aspects to that child's story, you don't want to get too worried about that unless it's extreme. 

Dr. Jessica

No, I love that you bring that up because this is a frequent story in our office where a baby will be, let's say, 95th percentile for weight, 95th for height. And as they get to be like nine months a year, they slim down. Their growth isn't as. They're not at the same percentiles, and parents worry. But it's great to hear you say that this is a normal phenomenon. 

Dr. Mitch Geffner
It certainly can be. The trick of all of this is always to know when something is most likely to be normal, when it might not be an hour just requires a lot of savvy and clinical experience. And if the pediatrician needs a little extra support, that's where I exist. 

Dr. Jessica

Yes, absolutely. That was great. All right, well, thank you. Thank you. Thank you. I really, genuinely appreciate it. Thank you. Thank you.