What We Know — And What We Don't About Our Sex

boy and girl

Nurture or Nature

Our brains aren’t set in stone, even if our sex is. If we learn from each other, then these differences become opportunities, not divisions.

By: Marianne J. Legato, FACP and Laura Tucker

To begin, I’d like to present you with an overview of the science as we currently understand it, via true-or-false statements that come from questions I’ve been asked at lectures and by my patients. As you read, I’d like to remind you that while there do seem to be gender-specific ways of thinking, remembering, and experiencing emotion, those differences do not necessarily connote superiority. Dr. Kandel’s groundbreaking research assures us that our brains aren’t set in stone, even if our sex is. If we learn from each other, then these differences become opportunities, not divisions.

True or False: Sex is determined by our biology.
True and false. Although our sex is determined at the moment of our conception, and we stay that sex for the rest of our lives, we actually become more or lessfemale or male over the course of our lives. Let’s take a look at how this happens.

The sex chromosome contributed by our fathers pushes us to form male or female sex organs. Those organs, in turn, release hormones that cause dramatic and sex-specific changes to every organ and tissue in our bodies — including the brain — and program them to respond in sex-specific ways down the line. Varying levels of hormones over the course of our lives continue the process of sexing us.

In other words, our genes set us up for the sex we’ll be, and our hormones salt the stew. The complex interaction between these two factors — especially during specific windows when their levels drop or surge as they do during puberty and menopause — make the two sexes different and each of us different from one another as well.

Nature is only part of the explanation for the differences between us. In fact, one of the thorniest challenges faced by those of us who study gender differences is teasing out which differences are due to the genetic and hormonal components of our biology and which are the result of “nurture,” or how we’re conditioned and shaped by our environment.

Society certainly believes men and women are different and expects sex-specific behavior from us. Even when children are young, parents encourage sons and daughters to do quite different kinds of activities, and in fact, boys and girls seem to enjoy quite different things.

These very disparate paradigms of what it means to be male or female provoke important questions about the difference between the sexes. How many of the differences between us are the result of the gender roles that the society of the time imposes? Are our sex-specific talents, temperament, and world view inescapably hardwired into our central nervous system? Or is our sexually stereotyped behavior choreographed by our culture’s expectations of us?

Some of the differences between men and women are hardwired. But as soon as we’re born, the environment works in powerful ways to interact with, and even change, our hardwiring to shape the way we act and interface with others. The idea that our experiences can change our brains means that the strands of conditioning and biology are more closely intertwined than we’d even thought. Treating your daughter like she’s a girl may make her more so. The brain is never “done,” but continues to grow and change as long as we provide it with inspiration.

About the Authors:
Marianne J. Legato, FACP, is an internationally known academic physician, author, and lecturer. She is a professor of clinical medicine at Columbia University, where she founded and heads the Partnership for Gender-Specific Medicine. One of the world’s foremost experts on gender medicine and winner of many awards for her work, she is the author of The Female Heart, What Women Need to Know, andEve’s Rib. She recently edited the widely acclaimed academic textbook, Principles of Gender-Specific Medicine.

Laura Tucker is the coauthor of several health and medical books. She lives in Brooklyn, New York, with her husband and daughter.

Copyright © 2005 Marianne J. Legato, MD, FACP and Laura Tucker

Reprinted from: Why Men Never Remember and Women Never Forget by Marianne J. Legato, MD, FACP and Laura Tucker © 2005 Rodale Inc. Permission granted by Rodale, Inc., Emmaus, PA 18098. Available wherever books are sold or directly from the publisher by calling (800) 848-4735 or visit their website at www.rodalestore.com

Photo: Camille Panzera