Published on June 29th, 2020 and Updated on January 15th, 2021
It’s mind-boggling how fast your baby grows. With each doctor’s appointment, you get the latest update on height, weight, and percentiles, and it’s always shocking. Even without these numbers, you can see the change—the first onesie grows tighter, tighter, and then a larger size is needed. In every picture, your child looks a little different; your friends and relatives can’t stop saying, “she’s getting so big!”
Soon she’ll be tall enough for the “You Must be This Height” rides at the amusement park.
It’s hard not to wonder: How tall will my child be?
Stages of Growth
It may feel like your baby’s growth accelerates every month—but he actually had the biggest growth spurt of his life in your belly. In nine months, your baby went from a height of 0 inches to his birth height, which is generally around 18 to 22 inches. That rate of growth is generally never experienced again.
All people go through the following stages:
- Fetal growth – During this stage, insulin plays a central role to growth.
- Childhood growth – Children grow at a rate of about two inches a year up until they are eight years old. In childhood, boys and girls grow at similar rates. During this stage, nutrition plays a central role in the amount and speed of growth.
- Puberty – Children undergo a growth spurt, with boys growing more rapidly than girls. Regulating factors of puberty include:
- Growth hormone (secreted from the pituitary gland)
- The sex hormones estrogen and testosterone (which aid bone formation and activate growth hormone)
- Adult height and growth plate fusion – Most girls reach their adult height at 15, while most boys reach their full height at 17 or 18. While some growth may occur over the next few years, the majority of growth is finished by these ages.
Until your child has reached the adult phase, his height is not set in stone but determined by a variety of factors.
Factors that Affect Height
How tall will your child be? Some online child height projection tools take just two factors into account to predict your child’s height: the mother’s height and the father’s height. But if you have siblings, you know it’s more complicated than that: two sisters can be very different heights.
Adult height depends on many factors, including:
- Exposure to disease
Genetics vs Nutrition vs Disease: Which factor matters most?
Determining a child’s eventual adult height can be summarized as follows:
- Genetics set the boundary for how tall a child can be.
- Proper nutrition helps the child realize their potential height.
- Disease and environmental factors can hinder their growth pattern.
Therefore, as long as the child grows up healthy (with regards to diet and disease), their adult height can be determined through genetics.
Role of Genetics
Molecular biologist Chao-Qiang Lai explains in Scientific American that in European populations, height seems to be about 80% hereditary. In contrast, in Asian countries, a child’s future height may be only 65% hereditary—meaning that diet, disease exposure, and other factors can play a greater role in a child’s growth pattern and eventual adult height for different populations.
This difference in heritability is due to generational environmental effects. “When a given environment maximizes the genetic potential of a population for a given trait, this population tends to have a higher heritability for that trait, and vice versa.” So, countries that have offered strong nutritional environments for generations have increased the heritability of height. However, despite the differences between populations, genetics are still the largest factor of adult height in all people.
These genes aren’t all summed up in “tall” or “short” genes. Similar to traits like hair color and eye color, your child’s future height is polygenic—that is, a number of different genes play a role in determining height. In fact, there are as many as 3,290 gene variants that affect height.
Researchers in Nature found that, of 21 studied chromosomal loci, 13 contained “a known skeletal growth gene.” The most well-studied genes involved in height regulate the activity at cartridge growth plates. These areas at the end of bones grow new bone, effectively adding length to a leg or arm bone (and thus increasing height).
Examples of important genes that influence height include:
- GDF5 – The “growth differentiation factor 5” gene helps regulate the child’s normal growth of cells and tissues, including bone and cartilage
- IHH – This gene encodes a protein involved in bone growth
- While many genes are involved in determining height, none has a huge effect on its own.
While many genes are involved in determining height, none has a huge effect on its own. Researchers Brian McAvoy and Peter Visscher found that “The DNA variant with the largest effect on height only has an impact of about five millimetres, and most of the other variants have a much smaller effect.”
5 mm or 0.19 inches hardly affects whether your child is tall enough to be the first pick at volleyball. Instead, height is the result of the complex interactions of the many genes that regulate the proteins and hormones involved in child growth.
Did your mother ever tell you that you had to drink milk to grow up tall and strong? While milk is not the only possible source of the nutrients, she may have been onto something. At a population-wide level, better nutrition is associated with increased future height.
When it comes to nutrition for growth, all the basics you’ve been taught about diet apply. To reach their full potential height, your child needs:
- Fresh fruits and vegetables
- Adequate protein
- Other vitamins that support bone growth, including vitamins D and K
Exposure to Disease; Access to Medication
Researchers Carlos Bozzoli, Angus Deaton, and Climent Quintata-Domeque share that wealthier, healthier populations are statistically taller. By plotting infant mortality vs. adult height, they find that nations where children are exposed to more health risks have shorter populations. Based on this research,
“The early-life burden of undernutrition and disease not only is responsible for mortality in childhood but also leaves a residue of long-term health risks for survivors, risks that express themselves in adult height and in late-life disease.”
Giving additional credence to these findings, researchers Albertine Berard and Martin Blaser found that children who face less exposure to microbes during their developmental period grow up to be taller adults. These researchers suggest that the availability of antibiotics that kill off microbes help children to reach their maximum potential adult height.
While some medications (i.e., antibiotics) may aid in children’s growth, childhood exposure to other medications may impede it. There is a body of research suggesting certain ADHD medications are tied to shorter stature, for example.
How to Get an Accurate Child Height Projection
As a parent, you’re dedicated to nourishing your baby with a full range of nutrients, as well as keeping them safe from disease. So you know you’ll have some influence on your child’s height through your nurturing. But what about when it comes to nature? You might want to know if your baby boy will turn into an extra-tall adult or stay short and sweet.
The most accurate way to get a picture of your baby’s eventual elevation is to look at the genes that influence height. For that, you need a DNA test.
Does your mind ever wonder “What color hair will my baby have?” Are you looking for a safe, private way to gain more insight into your child’s adult height, as well as other genetic traits, like nutritional profile? Luckily, SneakPeek will be introducing the SneakPeek Early Traits DNA Test in Fall 2020.
Complete your at-home DNA test in just three steps:
- Take a quick rub of your child’s inner cheek with a cotton swab.
- Send the cotton swab back in a prepaid envelope
- In 2-3 weeks, receive your child’s genetic profile.
When the results arrive, you’ll gain insight into so much, including your child’s adult hair color, eye color, and yes, how tall they’ll be. With this test, develop an even deeper understanding of the beautiful being you’ve brought into the world.
Taking the DNA sample is pain-free, and your child’s data is privacy-protected.
The SneakPeek Early Traits DNA Test
Questions like “When does baby hair texture change?” or “Will my baby’s eyes stay blue?” are actually very normal questions to have about a baby. As a parent, it’s natural to want to know everything you can about your growing child. You’ll love them whether their hair changes texture or their eyes change color. But the more you know about your baby, the better you can care for them and prepare your family for the future. That’s why we’re creating the SneakPeek Early Traits DNA Test. With these results, you’ll better understand your child’s growth and development needs, including their genetic predispositions for sleep behavior and nutritional needs.
For a sneak peek into your baby’s future, let’s take a look together this fall.
- Perspectives in Biology and Medicine. The ecology of height. https://muse.jhu.edu/article/26156
- Nature. Hundreds of variants clustered in genomic loci and biological pathways affect human height. https://www.nature.com/articles/nature09410
- Economics & Human Biology. Genetics of human height. https://www.sciencedirect.com/science/article/pii/S1570677X09000793
- Gene cards. GDF5 gene. https://www.genecards.org/cgi-bin/carddisp.pl?gene=GDF5
- National Institute of Health. Is height determined by genetics? https://ghr.nlm.nih.gov/primer/traits/height
- Scientific American. How much of human height is genetic and how much is due to nutrition? https://www.scientificamerican.com/article/how-much-of-human-height/
- Demography. Adult height and childhood disease. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2809930/
- Medpage Today. ADHD tied to shorter stature in early childhood. https://www.medpagetoday.com/meetingcoverage/pes/79491
- WebMD. Round out your child’s plate. https://www.webmd.com/parenting/features/kid-nutrition-nutrients#1
- American Journal of Medical Genetics. Endocrine control of growth. https://www.ncbi.nlm.nih.gov/pubmed/23613426
- Healthline. When Do Boys Stop Growing? https://www.healthline.com/health/when-do-boys-stop-growing#median-height
- Healthline. Height in Girls: When Do They Stop Growing, What’s the Median Height, and More. https://www.healthline.com/health/when-do-girls-stop-growing#median-height