X-Chromosomes and Your Baby’s Intelligence: A Primer on Spotting Fake Science News

A beautiful picture of a new mother and her infant popped up on my Facebook feed, with an intriguing headline to go with it. “Research Reveals: Children Inherit Intelligence from Their Mother, Not Their Father,” the title claimed. It was on a site called Positivity something or other, and my inclination was that it must be exaggerates, but otherwise based on a straightforward reading of some recent study. But, it turned out to be fake news for genetics, a find that, sadly, is part of a larger picture that we’re seeing these days in multiple fields.

The un-named author –a warning sign of fake news– spent some time explaining how only boys have a Y chromosome, which must be from the father, so only the mother can give them an X. That much is true, but it’s not news. The article, plus others that are circulating about with similar titles, refer to ‘new’ research. In some cases, they don’t explain what the research is, while others do describe studies, but studies that don’t actually support the headline. Some of them have links or references to a 2016 article in Psychology Spot magazine that notes many non-genetic factors influenced a child’s intelligence. It also highlights the X chromosome contribution, but the research studies cited by the author on this topic are very old, some dating to the 1980s and 70s. This happens sometimes in magazine articles that are not reviewed by people with expertise in the highlighted topic.

To find the ‘new’ research that the 2016 article has in mind, you need to keep checking references and clicking. Doing that, I found that it comes down to this

study conducted at the University of Ulm, in Germany –published in 2001. That study showed that many genes responsible for cognitive abilities are located on the X chromosomes. The authors suggested that this explains why mental disability is more common in males than females. That’s very logical, but it doesn’t mean that mothers have more genetic influence than fathers on intelligence of children who are not mentally disabled.

Along with Psychology Spot magazine, the un-named author of the Positivity article also referenced two other sources. One was a piece on a website called “Dr. Witt’s School of Love”, where the aim is to sell Dr. Witt’s books. The other source was an actual research paper on mouse genetics from Nature, a very prestigious scientific journal, but the paper was published back in 1984.

To justify the old paper, the Positivity author wrote that, “The idea that mothers have a disproportionate influence on a child’s intelligence is not a new one”, but this proved problematic for a couple of reasons. First, the 1984 paper actually didn’t describe the mother’s influence on a child’s intelligence. Instead, it described how genes from the father of a mouse embryo might be necessary in order for biological tissue outside the embryo to develop normally. There could have been some speculation about inheritance of intelligence deep in the paper, but that’s not something that the actual mouse study results demonstrated. To quote the researchers’ conclusion from the paper abstract: “Our combined results indicate that while the paternal genome is essential for the normal development of extraembryonic tissues, the maternal genome may be essential for some stages of embryogenesis.”

Second, when one cites an old study to show how some idea goes way back, one then needs to cite more recent studies showing how that old idea has withstood further testing. Instead, the Positivity article could cite only magazine articles, which in turn cited old studies.

I was saying “huh?”, and probably so are you, because nobody is expected to look up the research paper. You are expected to click “like” and “share” based on the headline. Don’t do that. It makes fake news circulate.

Since 1984, and since 2001, genetics has advanced in leaps and bounds. In the intervening time, the human genome was mapped and we’ve been finding that the influence of genes on human traits is immensely complex. Meshed in with genetics is a newer field called epigenetics, which concerns how genes are regulated and their expressions modified in ways that can be passed down through generations without altering the content of what the gene produces when it is turned on. The information coming out of the thousands of research papers that have been published since the ‘new’ research of 16 years ago is mind boggling, and there are plenty of really good publications and websites explaining it.

David Warmflash
Dr. David Warmflash is a science communicator and physician with a research background in astrobiology and space medicine. He has completed research fellowships at NASA Johnson Space Center, the University of Pennsylvania, and Brandeis University. Since 2002, he has been collaborating with The Planetary Society on experiments helping us to understand the effects of deep space radiation on life forms, and since 2011 has worked nearly full time in medical writing and science journalism. His focus area includes the emergence of new biotechnologies and their impact on biomedicine, public health, and society.

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