Fascinating study into why women are the stronger sex
MORE men than women are falling victim to the coronavirus, dying at nearly twice the rate. Nobody knows why but Dr Sharon Moalem probably has an idea. His book, The Better
Half, is about the genetic superiority of women due to their extra X chromosome, which gives women stronger immune systems and a greater ability to fight disease.
The notion that women are genetically better off than men is a compelling possibility — and surely one we might have thought of before. Over the past 25 years, global health data has consistently pointed towards poorer health outcomes and shorter life expectancies for men, according to an article in the
British Medical Journal looking at gender differences in the fate of patients with Covid-19. Research and policy have not taken this disparity into account.
Men have traditionally been perceived as the stronger sex and societies have long favoured boys, but across the human lifespan it is women who win out. Girls born prematurely are more likely to survive than little boys, and at the other end of the spectrum, the vast majority of people over 100 years of age are women. A raft of killer diseases affects men more viciously than women — heart disease, cancer, liver disease, kidney disease and diabetes. And a sobering thought: although 105 boys are born for every 100 girls, by the age of 40, the numbers have evened out.
We might be tempted to put this down to lifestyle — the fact that men are more likely to smoke, do hard physical jobs and engage in risky behaviour. While this is all true, Moalem says it doesn’t fully account for the trend, which holds across centuries, countries and cultures. He explains that it’s down to the two X chromosomes in every gene in a woman’s body, one from her father, the other from her mother. The healthier X is activated, the other silenced, but the silenced X continues to play a role, re-activating when needed to help maintain well-being and health; whereas men, with just one X chromosome, are forced to rely on it regardless of its quality. “Having another X chromosome provides extra genetic horsepower to each cell, which is an advantage that females have over males,” Moalem writes.
Despite these very real differences, scientific research has drawn largely on male subjects for clinical trials, working on male cells and even preferring male mice to females because they yielded more coherent results. The result is that, “With a few exceptions, we clinically treat women just like we treat men,” Moalem says. It’s an argument the feminist activist Caroline Criado-Perez made last year in her ground-breaking work, Invisible Women: Data Bias in a World Designed for Men. Moalem’s book backs up her contention that marginalising women in medical research has adversely affected women, even put lives in danger. Products have been withdrawn and guidance altered when the female response became apparent. In 2013, for example, the guidance for Ambien was reviewed because the US Food and Drugs Administration (FDA) finally recognised that women needed a lower dose than men.
One reason behind this bias in research, Moalem implies, is that science is dominated by men. He nicely weaves alternative versions of scientific discoveries — where women got there first but were suppressed in later accounts — into his narrative, introducing pioneering figures like Nettie Stevens that I for one had never heard of. Stevens, who worked on mealworms, was the first scientist to identify the Y chromosome, but the finding is generally ascribed to Edmund Beecher Wilson, who rushed the publication of his own research on the topic through after seeing
Stevens’s findings. (Easy to do, given that Wilson happened to be on the editorial board of the journal that published his paper.)
The Better Half is popular science, aspiring to translate intricate concepts about genetics into ordinary language. As such it is replete with colourful anecdotes and recollections from Moalem’s own experience that humanise abstract concepts. He shares a wealth of fascinating factoids, such as women’s preternatural ability to recognize colour. Some women have tetrachromatic vision, a sort of “visual superpower.”
Perhaps inevitably, though, The Better Half can at times feel oversimplified. To a non-geneticist, obliged to take his word for it, it’s unnerving when Moalem leaps from genetics to immunology to neuroscience to the functioning of the potato (a topic he has studied in depth) and back again. The book suffers, too, from repetition. Moalem makes the point that women live longer than men; then says it again, and again.
But Moalem’s essential thesis is valid and important, and deserves attention both within the scientific community and beyond — that women’s genetic difference from men results in a different response to both diseases and treatments, which research ought not just to account for but also study and attempt to understand.
This is a readable and lively book, making an argument long overdue, and one that the coronavirus may unfortunately help to illustrate.