Sharon Moalem

Biology is not destiny

Inheritance: How Genes Change Our Lives and Our Lives Change Our Genes by Sharon Moalem, M.D., Ph.D. (Grand Central Publishing, $28).

Let’s all give a big shout of gratitude that Dr. Moalem has written this easy-to-follow primer in genetics, because he does a fantastic job of myth-busting, rumor-debunking and fear-comforting.

In short, his premise is that biology is not destiny. Our genetic makeup both influences and is influenced by our lives; we have as much power show more over our genes as our genes have over us—with a few notable exceptions. And he also makes clear that, for all that humans are similar as members of the same species, we are also, each and every one of us, first and foremost individuals.

Get that? There is no “average” human, which is why a medicine, exercise regimen or diet that really helps your friend may not work—or have really strange/dangerous consequences—for you.

Even better than Moalem’s clear writing is his frequent use of stories to illustrate his points, which puts this book solidly in the camp of general reader-friendly. He covers all the basics, which makes this a necessary volume to offset the outlandish and separate the science from the science fiction. show less

This turned out to be an utterly fascinating book! I had been thinking, from its title, that the book would be about disease. It is, however, about something else entirely - how evolution and our genetic make-up are closely intertwined. Based on the modern research (Okay, I'll admit I haven't read much about DNA since nursing school), I was astounded by recent discoveries that show how evolution is often based on genetic traits acquired not by heredity, but by environment. This book and the show more subject are so vast that the ideas could be overwhelming. The author takes this subject in a stride and uses an easy-going and often humorous way of presenting what could otherwise be dry material. Here is one man I'd love to have as a college professor! I must say that, although I might not later remember the technical details of this book, I thoroughly enjoyed its presentation. show less

While reading this book, I was constantly calling up friends to tell them, "This is so cool! Did you know...?" Absolutely fascinating book on why humans evolved diseases. Very highly recommended.

And here I was hoping it would be more like a guidebook. Author Sharon Moalem (who is a he, despite the name) has written what could be considered an update to Everything You Always Wanted To Know About Sex But Were Afraid To Ask. There a lot more evolutionary psychology and biology than there was in EYAWTKASBWATA, though. Moalem isn’t presenting his own research, but reviewing studies from a lot of other authors. Full of interesting little results (the age of puberty in girls depends on show more the amount of hip fat; the first self-service items in American drug stores were menstrual pads (supposedly because women were too embarrassed to ask a male clerk for them, and then leading to a lot of other self-service items); there are at least 20 different theories attempting to explain female orgasm) but also more detailed discussions of things like intersex conditions. I noticed a couple of things that bear on previous reviews.


Potential evolutionary explanations for male homosexuality: It seems that one study showed female relatives of gay men had more offspring than average women. The authors suggests – not quite so bluntly – that there was a heritable factor that made carriers want to have lots of sex with men – regardless of the carrier’s gender. That could at least partially explain the evolutionary puzzle of homosexuality; there are enough females with the allele to overwhelm nonbreeding male carriers. Could be; other explanations possible.


Athletes with intersex conditions. Moalem lists a couple of examples:


Indian runner Santhi Soundarajan’s was disqualified in 2006 for having (according to anonymous rumor) “more Y chromosomes than allowed”. Moalem doesn’t have further details but notes that Soundarajan had passed many previous sex determination tests. He speculates that the previous tests were limited to physical genital inspection, and that Soundarajan has Androgen Insensitivity Syndrome. An earlier (1985) case was Spanish hurdler Maria José Martinez-Patiño, who turned out to have Y chromosomes and AIS. Interestingly, it isn’t clear if AIS would necessarily give you an advantage in women’s athletic competitions; there’s enough variety in expression that AIS people range from externally indistinguishable from 46XX women to externally indistinguishable from 46XY men (despite all having 46XY karotypes).


In a chapter on The Pill, Moalem notes that it has an interesting effect on women’s odor preferences. Studies where women sniffed used men’s clothing (usually called “t-shirt” studies) found that women preferred the scent of men whose immune system genetics differed from their own (the evolutionary idea here being that women would seek mates in “outgroups” rather than among their own group, to avoid inbreeding). Women on The Pill, OTOH, preferred the scent of men with similar immune system profiles. The authors of this study suggested that being on The Pill is essentially fooling the body into thinking you’re pregnant. Women who aren’t pregnant therefore prefer “exotic” men, while pregnant women prefer “familiar” (and therefore presumably “safe” and “protective”) men. Could be, but a lot of evolutionary psychology excruciatingly difficult to prove conclusively. At any rate, I don’t think there’s been a tremendous increase in first cousin marriages since The Pill.


Not bad for a reasonably technical discussion of a lot of aspects of sex and gender. Interestingly, my copy was deacquisitioned by the Denver Public Library even though it was only three years old. Too controversial? show less