5 Traits That Babies Get From Their Mother Only

Published on November 24th, 2020

When your baby is born—and even before—you may find yourself taking a closer look at your own features. Your female relatives may claim moms always pass down the family nose. Your partner might point out that your sister’s children all got her red hair.

You might even find yourself pouring over old scrapbooks and photo albums, comparing your newborn baby’s pictures to your own childhood snapshots to determine whether or not she’s destined to inherit your sparkling eyes, your height, or your freckles.

How much of your baby’s features comes from momma?

It all comes down to genes, and what genes are inherited from mother only vs what genes are inherited from father only. 

How Your Genetics Work 

It’s easy to think of a baby’s genetic makeup as 50% mom and 50% dad. In reality, it’s more complicated than that. To understand why moms are responsible for certain characteristics, it can help to learn a bit about how genetic traits are inherited.

Polygenic Traits 

Most human traits are polygenic, which means they’re determined by the combination of several genes from both parents. For example, there are at least 700 sequences in your genetic code that can affect height. Similarly, your skin, hair, and eye color are based on a hodgepodge combination of genes—which explains why our eyes have such a wide spectrum of colors. So when asking what color eyes will my baby have? or “where does the hair gene come from” the answer is a bit more complex than just mom or dad. 

Uniparental Inheritance through Chromosomes 

Certain genes are transmitted exclusively from one parent to the offspring. To understand this one-sided genetic inheritance and, more specifically, maternal inheritance, let’s take a quick dive into the thrilling world of chromosomes. 

Human cells contain chromosomes, the structures that hold genes—our unique genetic information. Each cell has 23 unique chromosomes, responsible for different functions and different genetically inherited traits. 

These chromosomes can be split into two categories:

  • Autosomal – Most humans inherit 22 pairs of matching chromosomes, one from each parent. These pairs code for the same traits, and it’s the combination of these genes from both mom and dad that determine what features a child exhibits.
  • Sex-linked –The genes contained within this 23rd pair of chromosomes lead to sex-linked traits. Since X and Y chromosomes determine a child’s gender, this can also help illuminate which traits came from mom versus dad.

    Here’s how that breaks down by gender:
    • Girls receive an X-chromosome from each parent, therefore their X-linked traits will be partially inherited from dad, too.
    • Boys, on the other hand, only receive a Y chromosome from their father and an X chromosome from their mother. That means all of your son’s X-linked genes and traits will come straight from mom.

Because boys get their X chromosomes —and the affiliated traits—from mom, it’s a bit easier to answer which sex-linked traits come from Mom and which come from Dad for boys. Since girls have two X-chromosomes, it’s not necessarily possible to know which sex-linked traits come from mom versus dad without diving into the family’s genetic code. 

Maternally-Inherited Traits—Fact or Fiction 

From mitochandrial DNA to X and Y chrosomosomes, the human genome is a mystery that scientists are still unraveling. But one thing’s for sure, some behaviors and traits have been linked to maternal influence—biological and otherwise.  

#1 X-Linked Traits Moms Pass Down to Their Sons 

When it comes to certain traits, it’s no mystery which parent your child has to thank—whether it’s the spitting image of his dad’s nose or his mother’s love of soccer. And that’s especially true for X-linked traits in sons. 

The Supporting Evidence: Because sons only get one X chromosome from Mom and one Y chromosome from Dad, all X-linked traits can be traced back to the maternal influence. That may include:

  • Red-green color-blindness Red-green color-blindness—or being unable to distinguish between green and red—is a recessive X-linked trait. That means if mom has the recessive X-linked DNA, the trait will manifest in her son. This is why red-green color blindness in girls is particularly rare—both parents would have to have the recessive DNA.
  • Hemophilia A – Hemophilia A is a genetic condition that causes blood to clot improperly. People who are diagnosed with hemophilia can bruise easily and may suffer from abnormally heavy bleeding from even small cuts. Like red-green color blindness, hemophilia A is an X-recessive trait. 

The Bigger Picture: Thanks to x-linked traits, sons can trace some characteristics right back to Mom. 

#2 Signs of Aging (Thanks to Mom’s Mitochondria) 

As you age, your face begins to show the signs—crow’s feet, forehead wrinkles, laugh lines. But you might have mother dearest to thank for when and how these signs of aging materialize. Specifically, your mom’s—and your—mitochondria.

The Supporting Evidence: The mitochondria is a tiny—but powerful—part of a cell. It’s responsible for the cell’s respiration and energy production processes. And, mitochondrial DNA (or mDNA) is inherited strictly from the mom.

Because mDNA can only be inherited from the mother, meaning any traits contained within this DNA come exclusively from mom—in fact, the father’s mDNA essentially self-destructs when it meets and fuses with the mother’s cells. 

Sorry, male DNA!

Unlike X-linked traits, mitochondrial DNA affects sons and daughters equally. That means both boys and girls receive their mitochondria—and the genetic traits affiliated with the mitochondria—from Mom. 

The mitochondria has significant influence over—among other things—the aging process. Our mitochondrial DNA sustains damage from:

  • Free radicals from the sun’s UV rays 
  • Toxins like cigarette smoke 
  • Pollution

These factors mutate mitochondrial DNA and affect the way we age. But there’s more to it than just personal exposure and environmental factors.

According to researchers at Karolinka Institutet and the Max Planck Institute for Biology and Aging, your child—boy or girl—will inherit your mDNA, whatever state it’s in. Just ask Dr. Nils-Göran Larsson, professor at the Karolinska Institute and lead investigator at the Max Planck Institute for Biology of Aging. Dr. Larsson has headed many studies that focus on mitochondrial DNA:

“Research showed that our mothers’ mitochondrial DNA seems to influence our own aging. If we inherit mitochondrial DNA with mutations from our mother, we age more quickly.”

There’s even research to suggest that children of older parents inherit suboptimal mitochondria—meaning mitochondria that’s not at its healthiest—which stays with children as they age.

If you were an avid fan of Marvel’s X-Men, you probably know that mutated genes can be passed down from one superhero to their progeny. In a similar fashion, free radicals in the sun’s UV rays and other environmental factors can damage mitochondria—essentially mutating it. This mitochondrial mutation is what’s passed down to your child. 

The Bigger Picture: While inherited mitochondria does play a role in your child’s aging, there are other factors that can make a big difference in her long-term skin health. That includes wearing sunscreen, staying away from cigarettes, and eating a diet rich in antioxidants.

#3 Intelligence: X-Linked & Mitochandrial 

When your daughter comes home with another A+ on her math test or a big win at the school spelling bee, you can pat yourself on the back for her achievements—but only to a certain extent.

The Supporting Evidence: There is increasing research that demonstrates mom’s role in her children’s intelligence—aside from her role as the math tutor, spell-checker, and project helper.

  • The brain is jam packed with mitochondrial DNA – The brain is a highly complex organ, probably more so than any other part of the body. Tissues that require more energy, including the brain, have higher densities of mitochondria. Again, this mitochondrial DNA comes exclusively from Mom, meaning those brainiac genes are largely hers.
  • Intelligence is carried on the X chromosome – While there is no single “intelligence gene,” the X chromosome carries genes responsible for intelligence and other social-cognitive skills. Because mom has two X chromosomes and dad only has one, more of the intellectual X chromosome genes are likely coming from the mother when it comes to sons since Mom is the only one who can contribute the X chromosome (and all its brainy traits).

    As for your daughter, she’ll have both Mom and Dad to thank for her brains because she gets an X from each parent—but maybe, thanks to Mom’s mitochondrial contribution, Mom gets a tiny bit more of the credit for her baby girl’s smarts.  

The Bigger Picture: While mom’s genes can provide a leg up, intelligence is hugely dependent on myriad environmental factors, from family life to learning resources.

#4 Sleeping Style—Nature or Nurture? 

When you put your son down after a long day and he falls soundly asleep, that godsend could be thanks to your genetics. But if he’s fussy and temperamental, or takes forever to finally nod-off, that could be your genes in action, as well. 

The Supporting Evidence: A study in Sleep Medicine suggests that youngsters inherit their sleeping patterns from mom. The study showed a distinct correlation between maternal insomnia and several sleep metrics in the child, including: 

  • How long the child slept
  • How much time was spent in each stage of sleep
  • How quickly (or slowly) the child fell asleep
  • What times the child woke up

The scientists have yet to discover if these traits are thanks to autosomal, mitochondrial, or sex-linked genetics, but it’s certainly the next step for this research.

The Bigger Picture: When it comes to sleep behaviors, a genetic link is only part of the equation. Factors like sleep environment, health, and a child’s stage of development all impact a child’s sleep behaviors.

Sleep Medicine says that traits inherited from the mother can influence a child’s susceptibility to sleep disorders and difficulties, but without a glimpse into the genetic code itself, it’s impossible to say how much is DNA and how much is external factors.

#5 Height—A Genetic Tug of War 

Will your daughter grow up to a height worthy of varsity basketball? And will she have you to thank for her long limbs? Or will her shorter stature be a little genetic gift from Mom?

The answer is a little less of a yes-or-no and a little more of a competition between your and your partner’s genes.

The Supporting Evidence: There is no one “tall” gene. In fact, at least 700 genetic variations affect your child’s height. But scientists have gleaned that Dad is responsible for most of the growing thanks to a growth factor known as IGF protein.

IGF proteins are strongly expressed in paternal genes. Mom’s genes, on the other side of the tug-of-war rope, an IGF protein inhibitor called IGF2R. That means Mom’s genes try to cancel out Dad’s growth factor genes.

Scientists have tried to understand why Dad’s genes fuel growth and Mom’s try to take that growth down a notch. One theory claims it may have something to do with the evolutionary benefits of a tall (or not so tall) child for each parent. 

  • Dad’s evolutionary programming wants his children to grow up big and strong so that they can survive and populate the gene pool with his genes, thus fulfilling his biological imperative of passing on his DNA to future generations. Dad’s genes tell a baby—still in utero—to soak up all the extra nutrients possible for increased growth. 

But where do those nutrients come from? 

Mom.

  • Mom’s evolutionary programming wants to survive pregnancy and childbirth! Pregnancy can take a toll on women, especially when it comes to health and nutrition in the early age of human evolution. So Mom’s genes suppress the child’s growth in utero to help manage the baby’s use of her nutritional resources so they can both prosper.

The Bigger Picture: Dad’s IGF protein growth factor will encourage his kid to grow tall. Mom’s IGF2R protein inhibitor gene will try to cancel out some of those growth factors. But those are just two genes out of hundreds that go into determining your child’s height. While Mom’s genes certainly have a part to play when it comes to your child’s height, it doesn’t matter whether you’re of average height or a giantess.

It’s all up to the genes. 

But you may find more answers than you ever thought possible with SneakPeek.

Quit the Guessing Game With SneakPeek Traits 

Despite the research, pinpointing exactly how your kid will turn out—and especially why they’ll turn out that way—is like finding a needle in a haystack. Comparing Mom and Dad’s traits will allow you to make educated guesses (at best) but to learn about your child’s traits, you’ll need to look at his DNA, not yours. And for that, you can use the SneakPeek Traits test

While you won’t foretell if your daughter gets into Harvard or your son wins a Nobel Prize, you might be surprised at just how much valuable information is written right into their DNA. 

  • Height as an adult
  • Nutritional profile
  • Unique sleep behaviors
  • Eye color and pattern
  • Hair color and texture
  • And so much more!

Information about your baby’s traits is only a quick cheek swab and lab test away. There’s no reason to spend the next 18+ years musing over their future when you can find out earlier than ever with SneakPeek Traits. If only the test showed whether your kiddo shares your inquisitiveness and curiosity, too.

 

Sources: 

NPR. Which Genes Make You Taller? A Whole Bunch Of Them, It Turns Out. https://www.npr.org/sections/health-shots/2017/02/01/512859830/which-genes-make-you-taller-a-whole-lot-it-turns-out

Family Education. 8 Traits Babies Inherit From Their Mother. https://www.familyeducation.com/pregnancy/traits-babies-inherit-from-their-mother

New York Times. Why Do We Inherit Mitochondrial DNA Only From Our Mothers? https://www.nytimes.com/2016/06/24/science/mitochondrial-dna-mothers.html

The Conversation. Do you share more genes with your mother or father? https://theconversation.com/do-you-share-more-genes-with-your-mother-or-your-father-50076

LibreTexts. Mendelian Inheritance. https://bio.libretexts.org/Bookshelves/Human_Biology/Book%3A_Human_Biology_(Wakim_and_Grewal)/08%3A_Inheritance/8.4%3A_Mendelian_Inheritance

National Center for Biotechnology Information. Understanding Genetics: A District of Columbia Guide for Patients and Health Professionals. https://www.ncbi.nlm.nih.gov/books/NBK132145/

Merck Manual. Genes and Chromosomes. https://www.merckmanuals.com/home/fundamentals/genetics/genes-and-chromosomes

NBC News. Are you destined to inherit your mother’s body? http://www.nbcnews.com/id/35254750/ns/health-womens_health/t/destined-inherit-your-moms-body/#.X2qaVJNKiL4

National Center for Biotechnology Information. Body mass index associations between mother and offspring from birth to age 18: the Fels Longitudinal Study. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5478810/

Sleep Medicine. The association of mothers’ and fathers’ insomnia symptoms with school-aged children’s sleep assessed by parent report and in-home sleep-electroencephalography. https://www.sciencedirect.com/science/article/pii/S1389945717303039 

The John Hopkins Newsletter. Children and mothers share sleep patterns. https://www.jhunewsletter.com/article/2017/09/children-and-mothers-share-sleep-patterns

University Hospitals Case Medical Center. Mother’s genes can impact aging process. https://www.sciencedaily.com/releases/2013/08/130821132710.htm 

Facts, Views & Vision: Issues in Obstetrics, Gynaecology and Reproductive Health. Can we define maternal age as a genetic disease? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4086015/ 

Independent. Children inherit their intelligence from their mother not their father, say scientists. https://www.independent.co.uk/news/science/children-intelligence-iq-mother-inherit-inheritance-genetics-genes-a7345596.html

Karger. Insulin-Like Growth Factor 2 in Development and Disease: A Mini-Review. https://www.karger.com/Article/Fulltext/343995

NPR. Which Genes Make You Taller? A Whole Bunch Of Them, It Turns Out. https://www.npr.org/sections/health-shots/2017/02/01/512859830/which-genes-make-you-taller-a-whole-lot-it-turns-out

Children’s Hospital of Philadelphia. X-linked Recessive: Red-Green Color Blindness, Hemophilia A. https://www.chop.edu/conditions-diseases/x-linked-recessive-red-green-color-blindness-hemophilia

SneakPeek aims to provide the most accurate and up-to-date information to help our readers make informed decisions regarding their health before, during, and after pregnancy. This article was written based upon trusted scientific research studies and/or articles. Credible information sources for this article are cited and hyperlinked.

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