The Differences Between the Sexes (Review of Why Gender Matters, by Leonard Sax)

Are there physically-based differences between men and women? Do they matter? Leonard Sax gives us some answers in Why Gender Matters: What parents and teachers need to know about the emerging science of sex differences (2nd edition), published in 2017.

The word in the title, “emerging” is not really accurate. Yes, the last 15 or 20 years has seen a largely unnoticed explosion in certain disciplines (like neuroscience) on just how different males and females are. But decades before that saw catalogues of differences from research.  Sax’s helpful book is a succinct update of something like Steven E. Rhoads’ elegant Taking Sex Differences Seriously (2004), only from the point of view of a clinician and educator.


Sax outlines the scientific data on the very real statistical differences between boys and girls with obvious implications for parenting and educating. It starts at the beginning. The biggest sex differences of gene expression in the brain occur in the womb, when testosterone male-ifies the boy brain. Then follow on significant differences in boys’ and girls’ ability to smell, hear and see. For example, women have average of 6.9 million olfactory bulb neurons at the bottom of the brain, men average 3.5 million. In one study, with repeated exposure to an odor, women’s ability to detect that odor improved 100,000 fold! The men, on average, did not improve at all. Baby girls (3-8 months old), on average, prefer to look at dolls rather than toy trucks; baby boys—you guessed it—the opposite.


And with regard to how children hear and speak, sexual differences may be more fundamental to learning than age is. For the average boy to hear you as well as the average girl, you have to speak about 8 decibels more loudly. That is about 3 clicks on the volume dial of a radio.


This doesn’t mean, of course, that sexual difference is absolute and non-complicated, but Sax tries to unwind it for us. For example, the studies also show the statistical overlap with which we have become so familiar (as in enGendered, chapter 6). In my upcoming book, for example, the overlap in distribution of traits comes up again and I sketch a chart of the relative lung capacity of men and women of the same height. Sure enough, they differ and overlap. The women range in lung volume from 83.3 to 105.8 percent of a predicted male lung capacity (TLC), with most women predictably falling in the middle of that range, around 95. The men range from 95.6 to 118.3, with most falling around the middle, 107. But this means that there will always be a few women will have a larger lung capacity than a few men.

On average on every trait, men and women are more similar than different, but that doesn’t make the differences irrelevant. Next time we will talk about how to handle Sax’s data on sex differences, when they are useful and when they aren’t.







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