This book is a bird’s-eye view of the history and evolution of the human species and its diseases. The author hopes that readers, regardless of disciplinary specializations in medicine and biology, might find inspiration for prospective research to inspire greater understanding – either in cutting-edge scholarship or in the regular diagnosis of patients. For those not in these fields, understanding human issues from the perspective of evolution might also be enlightening to one’s life philosophy.

Topics and some highlights from the book are in Q and A format as follows:

Q: Why Evolution?

A: Evolution Theory as envisioned by Charles Darwin, in terms of natural selection, sexual selection, and man-made selection, is a powerful and encompassing tool to understand many facets of human life and human existence. 

Q: Can evolutionary principles help to produce better diagnoses and therapeutics for major diseases such as cancer?

A: Cancer development can be seen as somatic cell evolution, beginning with cancer stem cell mutations to cancer cell migration (metastasis), and finally to resistance against cancer therapies. Modern single-cell sequencing allows scientists to trace the evolution of cancer cells, thus providing better diagnoses and therapeutics.

Q: What is the purpose of understanding gene evolution?

A: By elucidating gene evolution, one can understand organ evolution. One can also discover new hormones, receptors, and signaling molecules based on their co-evolution, followed by the designing of new therapeutics.

Q: Can we observe evolution in action?

A: Yes, there are many such examples. The 40-year evolutionary study of Charles Darwin’s finches in the Galápagos by Peter and Rosemary Grant is a most famous example.

Q: Is there a connection between evolution and pain?

A: The sensation of pain is an evolved adaptation mechanism for self-protection. For example, pain allows us to avoid biting the tongue, feel bone fractures, sense abnormality in our internal organs, etc.

Q: Is there a connection between evolution and “transgenic” food?

A: Yes, the basic food items we consume now went through a long historical mutation and man-made selection process. Many modern vegetables and fruits as we now know, for example, were likely toxic in the ancient days to avoid being eaten.

Q: Is there a connection between evolution and monthly blood loss (menstruation)?

A: Our ancestors did not have menses because, once reaching puberty, they became pregnant, followed by lactation. Menstruation evolved in primates to promote embryo implantation.

Q: Can women avoid monthly blood loss without affecting ovarian functions and fertility potential?

A: Yes, by using an intrauterine device that releases progesterone.

Q: Is there a connection between painful childbirth and evolution?

A: We evolved a narrow pelvis following our upright walking and enlarged brains, both of which facilitated for high intelligence. These evolutionary traits make the passage of a big fetus with a large head through a narrow birth canal very difficult.

Q: Why are women suffering from more breast cancers nowadays?

A: As modern women have evolved into having more menstrual cycles, they contribute to monthly circulating increases of sex steroid hormones. These hormones are conducive to the formation of breast, ovarian, and endometrial cancers.

Q: Can evolutionary principles explain why we are suffering a lot more from autoimmune disorders and allergies?

A: Unlike our ancestors, our children now live in much cleaner environments. Early childhood exposure to environmental microorganisms provides protection against allergic diseases whilst a lack of exposure contributes to inadequacies in the immune system.

Q: Are obesity and mounting diabetes connected to evolution? 

A: Yes, our ancestors evolved many genes to crave food with high sugar content. Unfortunately, in modern society, processed food with enhanced sweetness is commercially far more accessible to satisfy our cravings. 

Q: Can sugar-free diet items help?

A: Not really. Our ancestors evolved multiple cellular mechanisms to detect nutrient-rich food.  Sugar substitutes only satisfy our taste bud receptors on the tongue but not other sensors for glucose.

Q: Why is hypertension or high blood pressure an evolutionary issue? 

A: Optimal salt is crucial for our survival. Most of our ancestors lived far from the seashore and evolved mechanisms to crave salty food. Salt became widely available in recent times, and the overconsumption of salt leads to hypertension.

Q: Why is the so-called “love hormone” oxytocin significant in evolution? 

A: Oxytocin or “the love hormone” is a peptide hormone that plays a crucial role in social bonding, reproduction, and childbirth. Secretion of oxytocin increases during intercourse, labor, and lactation are essential for the survival of a species. 

Q: Is there a relation between evolution and anxiety? 

A: Our ancestors evolved anxiety to anticipate potentially dangerous situations involving predators, extreme weather, natural disasters, etc.

Q: Why is there a subgroup of Europeans resistant to HIV infection?

A: Their ancestors from the middle ages survived the smallpox pandemic by evolving mutations in the gene for a chemokine receptor, which is important for viral entry into our cells.

Q: Can we identify criminals using minuscule DNA samples at the crime scene?

1. By tracing DNA evolution in a population, we can easily identify an individual in a community with DNA data available from only 2% of the population.

Q: What is behind the evolutionary argument of the male species eventually becoming extinct? 

A: The male-specific Y chromosome has been shrinking in size during evolution due to a lack of pairing with another Y chromosome to allow gene recombination and repair. In evolutionary terms, we are talking about the extinction of the male species in millions of years.

Q: Is there an evolutionary basis for religion? 

A: Our ancestors evolved religious behaviors so that groups of people with the same belief could worship together, take care of each other, and form strong bonds, thus promoting survival. 

Q: What are memes?

A: Meme was coined by Richard Dawkins to denote an idea, behavior, or style that spreads using imitation from person to person within a culture. Examples are fashion, currency, stocks, and religious symbols.

Q: Is there an evolutionary basis for “free will”? 

A: Our so-called “free will” is based on the evolutionary history of our genes, and the acquisition of our memes throughout our life experiences. In the future, the application of big data algorithms could trace and even manipulate our "free will".

Aaron J. W. Hsueh, PhD, is Professor Emeritus at the Department of Obstetrics and Gynecology of Stanford University. He is also the recipient of an honorary doctorate in Medicine from Umea University, Sweden. His pioneering achievement in fertility and reproduction was cited as one of the top 10 scientific breakthroughs in 2013 by Time Magazine, and he is the author of more than 400 papers.

The Enlightenment of Evolutionary Medicine: The Past and Future of Human Diseases is available now at a 25% discount. Enter code PROMO25 to redeem.

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