Epigenetics is a game changer. What is epigenetics? It is a field of study that looks at how and why genes are turned on and off.
Scientists are discovering that our genetics are not simply determined by the sequence of DNA we inherit from our parents. We also can inherit their pattern of gene expression; which of their genes are turned on or off. Gene expression can be influenced by environment: what we eat, our level of stress, whether we exercise, our exposure to toxins. And modern science is telling us that the changes in gene expression that occur because of the way we choose to live our lives, can be inherited not just by our children, but also by our grandchildren.
We have always known how important it was for our mother to eat healthy and live in a healthy environment. What epigenetics is telling us is that it was also important for our health that our grandmother did the same. Why? Because your mother’s egg that was fertilized by your father’s sperm began developing while your mother was in her mother’s womb. So your grandmother’s diet and environment likely influences your overall health today.
Scientists are discovering the same about the diet and environment of men, who naturally produce sperm their entire lives. The New York Times has a piece called “Why Fathers Really Matter” highlighting the importance of epigenetics and cleaning living for men:
Doctors have been telling men for years that smoking, drinking and recreational drugs can lower the quality of their sperm. What doctors should probably add is that the health of unborn children can be affected by what and how much men eat; the toxins they absorb; the traumas they endure; their poverty or powerlessness; and their age at the time of conception. In other words, what a man needs to know is that his life experience leaves biological traces on his children. Even more astonishingly, those children may pass those traces along to their children….
The best-known example of the power of nutrition to affect the genes of fathers and sons comes from a corner of northern Sweden called Overkalix. Until the 20th century, Overkalix was cut off from the rest of the world, unreachable by road, train or even, in wintertime, boat, because the frozen Baltic Sea could not be crossed. Thus, when there were bad harvests in Overkalix, the children starved, and when there were good harvests, they stuffed themselves.
More than a decade ago, three Swedish researchers dug up records from Overkalix going back to 1799 in order to correlate its children’s health data with records of regional harvests and other documents showing when food was and wasn’t available. What the researchers learned was extremely odd. They found that when boys ate badly during the years right before puberty, between the ages of 9 and 12, their sons, as adults, had lower than normal rates of heart disease. When boys ate all too well during that period, their grandsons had higher rates of diabetes.
When the study appeared in 2002, a British geneticist published an essay speculating that how much a boy ate in prepuberty could permanently reprogram the epigenetic switches that would govern the manufacture of sperm a few years later. And then, in a process so intricate that no one agrees yet how it happens but probably has something to do with the germline (the reproductive cells that are handed down to children, and to children’s children), those reprogrammed switches are transferred to his sons and his sons’ sons.
So parents, tell your sons to eat healthy, and stay away from drugs and excessive alcohol. The health of their children and grandchildren may depend on it. The article also has an interesting correlation between paternal age and autism and asks if the rise in autism cases is a direct result of the rise of older fathers.
But what is missing from the mainstream discussion of epigeneics is a closer look at IVF. Whether it is being conceived in a dish, or the egg and sperm used in the process, children conceived with IVF have been shown to have different patterns of gene expression that those conceived naturally. Some scientists speculate that these changes may put IVF children at greater risk of diabetes and obesity. And if epigenetic changes in sperm and egg can be passed on to future generations, then it is likely the epigenetic differences in IVF children are ones they will pass on to their children and grandchildren.
So IVF is not just about the child couples so desperately want to hold. In today’s reproductive Brave New World, where natural biology is capriciously thrown overboard in favor of parental choice, the choices parents make in creating the next generation may be choices that extend to their grandchildren and great grandchildren.