Sure, you can blame Mom for grounding you on the night of the big high school dance, or for not handing over the car keys when your friends were all going to the beach, but can you really blame her for the extra inches that have settled around your stomach, or the heart disease you've developed in middle age?
It may seem that way when you read health news headlines. New studies often link this disease or that disorder to your mother's genes. But there's more to it than that.
It's true that you are, at least in part, a product of your mother. Whether you're tall and blonde or short and brunette is partly thanks to her genes. How she cared for you, both in the womb and during childhood, also had an influence on how you turned out.
Your health isn't entirely in your mother's hands, though. Heart disease, diabetes, and other illnesses are caused by a complex interaction between the genes you inherited from your mother and father, your diet, and other factors in your environment throughout your life. Some of these factors are so complex that even scientists don't fully understand them yet.
You Are Who You Inherit? Your Mother's Genes
Before you can understand how your mother's genes helped shape your future, you need a little Biology 101 lesson.
Genes are your body's blueprint. They carry the instructions for producing (expressing) all of the many proteins in your body that determine how you look and how your body works. Your genes are housed in structures called chromosomes. Most cells holds 23 pairs of chromosomes, for a total of 46.
You probably learned back in high school that you inherited one set of these gene-carrying chromosomes from your mother and another set from your father, and that the genetic contributions of each parent worked out to be roughly equal. That's why people may tell you that you have your father's eyes, but your mother's smile.
You also can inherit diseases, or a greater likelihood of getting a disease, from either parent. How much of an influence either parent's genes have depends on the disease. If your mom has a condition like Huntington's disease, because of the way the gene is inherited, you'll have a 50-50 chance of also getting the disease. If she has hemophilia, which is carried on the X chromosome, her sons will be at greater risk for the disease because they only have one X chromosome (XY). Girls have two X chromosomes (XX), which essentially dilutes the faulty gene.
With conditions like lupus or diabetes, the equation is a lot more complicated. Though your mom's (or dad's) genes may put you at risk for these diseases, you may also need to be exposed to certain factors in your environment to actually develop the condition.
Shuffling the Genetic Deck
The process of inheriting genes is fairly equitable, but scientists are learning that with a small subset of genes, which parent you inherit them from can make a difference in how that gene affects you. The process is called "imprinting," and it may have an impact on the genetic mistakes, or mutations, that produce diseases.
"If you have a mutation in an imprinted gene ... how that mutation will impact you depends entirely on which parent you got it from," explains Christopher Gregg, PhD, assistant professor of neurobiology and anatomy and adjunct assistant professor of human genetics at the University of Utah.
For example, one particular genetic glitch can increase your risk for type 2 diabetes, but only if you inherit it from your mother. Get the same gene variation from your father and you'll actually be protected against the disease.
When it comes to genes, know that your mother had no control over the traits that she passed to you. What she did have more control over was how well she nourished you while you were in her belly and during those first critical years of life.
Planting Healthy Roots
Researchers are discovering that the stage is being set for a baby's future health almost from the moment of conception, and the factors that go into a baby's development are far more complex than they had once thought.
"By the time it arrives in the uterus, very important biological decisions have been made and those are unchangeable," says David Barker, MD, PhD, professor of clinical epidemiology at the University of Southampton, England and professor of cardiovascular medicine at Oregon Health and Science University. "The seeds of a range of chronic diseases are being sown at that time."
Barker's theory, which is gaining momentum in the scientific community, is that what happens in the womb could impact whether a child develops conditions like cancer or heart disease many years down the road. Barker has found that babies who grow slowly in the womb and are born at a lower weight are at greater risk for a whole range of conditions, including coronary heart disease, stroke, type 2 diabetes, and high blood pressure.
Mom's Diet Counts
How the mother eats not only during her pregnancy but throughout her life can have an effect on her baby's health. "Babies live off the mother's body," Barker says. "And her body is the product of a lifetime of nutrition." In other words, mom's diet back in her own childhood can come back to either haunt -- or help -- her growing baby. He says mothers have to establish a lifetime of good nutrition, and not just eat a healthy diet while they're pregnant for it to make a difference to their children's health.
Kjersti Aagaard, MD, PhD, calls the first nine months in the womb -- as well as the child's first years out of the womb -- "programming for health." "There is no doubt that what happens in the first 1,000 days of life, from conception to 2 years of age, are fundamental influences not only on metabolism ... but also on our developmental health and well-being," says the assistant professor of maternal and fetal medicine and obstetrics and gynecology at Baylor College of Medicine. "Kids [who are] given an optimal environment and optimal nutrition very early in life, that groundwork is laid."
Scientists are learning that the choices moms make during pregnancy not only directly affect their baby's health, they might even lead to changes in the baby's genes. A new field called epigenetics is looking at how nutrition and other factors in pregnancy might alter the way the baby's genes function. One study done in rats found that eating a poor diet during pregnancy affected a gene linked to the production of insulin in the young -- a change that scientists say could increase the offspring's risk of developing type 2 diabetes later in life. It's not yet clear if the same is true for people.
So what does all this new research mean for Mom? It means that her contribution is to provide the healthiest possible vessel for her baby, which includes eating a balanced diet and following good habits (such as not smoking) not only while she's pregnant, but throughout her life.
How Mom cares for her baby outside of the womb is also important. A number of studies have touted the benefits of breastfeeding, finding that it can boost children's brainpower and reduce their risk for obesity as they grow.
Once children start on solid foods, feeding them a healthy, well-balanced diet can prevent them from growing into obese adults and from developing diseases related to obesity, such as diabetes and high blood pressure. Mom also has the important task of instilling in her kids the good eating habits that will lead them into a healthy adulthood.
What About Dad?
It seems like moms are under a lot of pressure for how their kids turn out, but don't the fathers also bear some of the responsibility for their children's future health and well-being? "There is an emerging body of evidence showing that fathers transmit information to their kids through the sperm," Gregg says. "Fathers can have an influence as well."
Not only do fathers contribute part of their child's genes, but they also play an important role in feeding, caring for, and nurturing that child during the early years.
However, our experts stress we shouldn't be placing "blame" on either parent. Scientists are still learning about the interactions between genes and environment and how they might determine a baby's future health, but what they can say with great certainty is that moms (and dads) shouldn't feel guilty about any of the genes they pass down to their children.
"You have no control over the sequence of DNA that you give to your kids," Gregg says. "All you can do is your best to be healthy yourself, and teach your kids to make good lifestyle choices."
Instead of blaming, we should be focusing on how we can improve health for all babies, Aagaard says. "What we're really trying to understand is, how do we program for health," she says. "How do we make sure this next generation is healthier than the last."