Book Review: The Better Half - On the genetic superiority of women

Dr Sharon Moalem's most recent book, The Better Half - On the genetic superiority of women, has a rather bold objective and that is to persuade you that women are genetically superior to men. While I typically welcome attempts to subvert the tired, old trope of women being the 'weaker sex', the suggestion that there is a genetic hierarchy aroused my suspicions. The sentiment didn't fit with my current understanding of human biology and, perhaps more importantly, I didn't understand what the term 'genetic superiority' even meant.

Dr Moalem, an American physician, scientist and author, believes that 'there's only one way to judge overall superiority between the sexes' and that entails identifying 'who is left standing at the far end of life'. According to Dr Moalem, women typically outperform men in terms of their resilience, stamina, immunity and brain function and, as a result, he believes that females should be crowned the superior sex.

Accordingly, the first half of the book is dedicated to examining the apparent biological advantages that females possess, namely, increased longevity, stronger immune systems and increased brain function. The chapter on immunity felt particularly prescient given the current COVID-19 pandemic. Dr Moalem prophetically states that 'scarcely a century ever passes without a genetic calamity befalling humanity, either environmental, microbial or both, and genetic females outlast males every time'.

Dr Moalem attributes each of these female-specific advantages to the fact than women typically possess two X chromosomes (one from their mother and one from their father), whilst men typically possess one X chromosome (from their mother) and one Y chromosome (from their father).

In each cell of the female body, one of the X chromosomes is switched off, yet, it is entirely random as to whether it is the maternal or the paternal copy of the X chromosome that is silenced. Some of the cells within the female body will express the genes on the maternal X chromosome and some will express the genes on the paternal X chromosome. Dr Moalem argues that 'having the use of two X chromosomes makes females more genetically diverse' and therefore more able to adapt to the challenges of life.

Dr Moalem is clearly a lively and engaging author, however, I had a number of issues with the first half of the book. In general, I found Dr Moalem's definition of genetic superiority to be problematic, it could easily be argued that genetic success is determined by an individual's ability to produce offspring and propagate their genes. I also questioned the need to identify a superior sex at all.

In addition, Dr Moalem attributes all of the genetic advantages associated with being female to the possession of two X chromosomes. Yet, it is stated within the book that approximately 6500 genes are used differently by males and females and many of these genes are not located upon the X chromosome. It therefore seems overly simplistic to attribute the 'superior' characteristics of females to the presence or absence of a second X chromosome.

Within the second half of the book, Dr Moalem examines the costs associated with possessing two X chromosomes, which predominately seems to be an increased risk of developing an autoimmune disease. He also explores why medical treatments designed for males may not be effective for females.

I found these later chapters to be more balanced and less contentious. Dr Moalem spends more time comparing the biological differences that exist between males and females and less time forcing the notion of female superiority. He even acknowledges that genetic females are more susceptible to certain medical conditions, such as, ischemic strokes and Alzheimer's disease.

I found these neutral comparisons to be incredibly valuable as they highlighted how medical treatments could potentially be improved if we had a greater understanding of the biological differences that exist between the sexes.

Despite Dr Moalem's problematic assertion that genetic females are superior to genetic males, and his extreme focus on the X chromosome, the book was actually really fun to read. The Better Half is full of personal anecdotes and historical stories of medical significance. The reader is exposed to an eclectic range of topics, including potato farming in Peru, apple tree pruning in Japan, the behavioural differences between male and female honey bees, the bubonic plague and the history of immunisation, to name but a few.

The book sits firmly within the popular science genre, it is easy to read and is accessible to everyone, not just those with a background in science or medicine. It provides a good introduction to the biological differences that exist between genetically male and female bodies (albeit in a rather sensationalist manner) and it champions the role of women in science. Dr Moalem also does an admirable job of explaining X chromosome inactivation and complex immunological concepts in an easy-to-digest manner.

While the book is likely to appeal to those with an appetite for popular science, it may fall short of the mark for scientists and medical professionals. In trying to prove his assertion that genetic females are superior to genetics males, Dr Moalem has a tendency to shy away from evidence that doesn't align with his personal definition of female superiority and as a result, the science he presents feels overly simplistic. As a scientist, I found myself craving complexity and nuance. Instead of being provided with evidence that fits neatly into discrete boxes, I wanted to hear about exceptions to the rule.

Overall, The Better Half is a fun and quirky introduction to some of the biological characteristics that are shared by people with two X chromosomes. Nevertheless, I would argue that Dr Moalem's proposition that these individuals are superior to genetic males is misleading, and also unnecessary.

Buy The Better Half: On the Genetic Superiority of Women from Amazon UK.