Is gender a social construction, caused when parents dress infant daughters in pink and paint sons’ walls blue? Or when they encourage sons to try out for sports and their daughters to try ballet? I always thought that there are minimal biological differences between men and women—until I heard Louann Brizendine’s presentation today, “The Gendered Brain.” Brizendine, a neuropsychiatrist who wrote the pathbreaking books The Female Brain and The Male Brain, took us on a tour of the male and female brains during each life stage, and pointed out the differences and similarities.

“The brains are more alike than different,” she said, “After all, we are the same species!” But from her extensive studies, it seems there are differences in the brains that really do make a difference. Some of it does have to do with society and culture, but some of it is biologically based.

She remembers one professor in medical school in the 1970s who responded to her question about a specific study (what were the effects on females?) that females weren’t tested because “their menstrual cycles would mess up the data.” At the time, she nodded her head, but years later, couldn’t believe that she’d bought into that answer! Back then, only males were tested in medical studies, so dosages weren’t set for women—males were thought to be “the human,” she noted, but in the extra chromosome that women have, there are hundreds of extra genes, and hormones affect males and females differently.   

Brizendine became involved in the women’s movement, which, she said, affected biology. Hormones, she explained, don’t change behaviors, but they do make behavior likelier. She took us through human life stages, distinguishing the differences in hormones that affect males and females, beginning with conception. For example, at just 8 weeks of fetal life, huge amounts of testosterone “marinate the male brain,” she said, which completely changes brain circuitry.

She displayed a diagrammed image of male and female brains that had the audience cracking up because it was so relatable—on the female brain, the biggest compartment was the “need for commitment” (followed by areas such as “chocolate,” “shoe and handbag matching,” and so on) and on the male brain, the word “sex” took up most of the brain, and areas like “listening” and “paying attention” were miniscule in comparison.

Brizendine navigated us through clear definitions of specific hormones and how they affect both genders in different areas of life’s timeline. What stood out the most for me, something I’ve never heard of before this presentation, is what happens to the male brain when their female partner is pregnant: their testosterone levels decrease by 30 percent and changes circuits in the brain. Brizendine said that evolutionarily, it makes sense for dads-to-be to change hormonally, because then there will be two adults ready to take care of an infant. Human babies are so helpless—and in the past, women often died in childbirth—so this makes sense.

Her scientifically-based explanations of what happens in the brain during different parts of life—the brain during childhood, the infamous teen years, as parents, and so on—had the audience laughing with empathy and understanding, and everyone came away with new reflections on the male and female brain. 

Brizendine’s books will be on sale Sunday. . . and after attending her thought-provoking presentation, I know I’ll be one of the first in line!