Apparently it is true. Your genes could have been altered even before your mother was born.
In December of 2013, there was a flurry of media activity reporting on a study published in Nature Neuroscience. Richard Gray, Science Correspondent for The Telegraph, describes the essence of the study:
Researchers at the Emory University School of Medicine, in Atlanta, found that mice can pass on learned information about traumatic or stressful experiences–in this case a fear of the smell of cherry blossom–to subsequent generations. The results may help to explain why people suffer from seemingly irrational phobias–it may be based on the inherited experiences of their ancestors.
The findings provide evidence of “transgenerational epigenetic inheritance”—that the environment can affect an individual’s genetics, which can in turn be passed on. One of the researchers Dr Brian Dias told the BBC: “This might be one mechanism that descendants show imprints of their ancestor. There is absolutely no doubt that what happens to the sperm and egg will affect subsequent generations.”
Prof Marcus Pembrey, from University College London, said the findings were “highly relevant to phobias, anxiety and post-traumatic stress disorders” and provided “compelling evidence” that a form of memory could be passed between generations. He commented: “It is high time public health researchers took human transgenerational responses seriously. I suspect we will not understand the rise in neuropsychiatric disorders or obesity, diabetes, and metabolic disruptions generally without taking a multigenerational approach.”
You’ll find another excellent article on this study at the Smithsonian.
That’s in mice. What about humans?
This one-minute video refers to a study of women pregnant during famine and how that affected their children. It shows that your genes could have been altered even before your mother was born.
In 2015, a study of holocaust survivors was published in Biological Psychiatry. A research team from New York’s Mount Sinai Hospital analyzed the genes of survivors and their children. As reported by Helen Thomson of The Guardian, this study is
…the clearest example in humans of the transmission of trauma to a child via what is called “epigenetic inheritance”—the idea that environmental influences such as smoking, diet and stress can affect the genes of your children and possibly even grandchildren.
And finally, from the folks at Minute Earth, here’s a summary of the weirdness of epigenetics.