What the Female Body Can Teach Us About Being Human

In honor of National Women’s Month

I’ll start with a statement that may sound controversial coming from a guy, but I promise it’s backed by science:

Without women, we don’t exist.

Groundbreaking insight, I know.

In honor of National Women’s Month, I recently reread the fascinating book Eve: How the Female Body Drove 200 Million Years of Human Evolution by science writer Cat Bohannon. Her central argument is simple but powerful: if we want to understand the story of humanity—how we evolved, how our bodies work, and even why we think the way we do—we have to start with the biology of women.

For millions of years, the demands placed on the female body including, pregnancy, childbirth, breastfeeding, and raising extremely helpless human babies have shaped the evolution of our species. Not just socially, but biologically.

This means a lot of what we think of as “human nature” is actually the result of evolutionary pressures on women’s bodies.

Take pregnancy. As any mother reading this already knows, pregnancy is no small undertaking. In fact, it is one of the most metabolically intense events found anywhere in nature. By the third trimester, a woman’s metabolic output rivals that of elite endurance athletes riding the Tour de France except instead of biking through the Alps, she’s growing an entire human.

Not a bad day’s work.

Human babies, as most parents quickly discover, are also remarkably unfinished at birth. A newborn giraffe can stand within hours. A human baby, on the other hand, mostly lies there looking surprised about being alive.

This is because our brains are enormous relative to our bodies. Over evolutionary time, our brains grew so large that babies must be born earlier in development in order to fit through the mother’s pelvis. The tradeoff is that human babies require years of care and development outside the womb.

In other words, our species literally evolved around mothers and caregivers.

Another fascinating piece of evolutionary biology has to do with body fat. Women typically carry about 6–11 percent more body fat than men, especially around the hips and thighs. Our culture has spent a lot of time criticizing those areas, but evolution has a very different opinion.

Those fat stores are rich in nutrients like DHA, which are critical for building large, complex human brains. So from an evolutionary standpoint, those hips and thighs helped grow the intelligence of our species one baby at a time.

Humanity clearly owes women a big thank you.

Pregnancy also reshapes the brain itself. Research summarized in Bohannon’s book shows that during pregnancy, certain regions of the brain involved in social awareness and emotional attunement actually reorganize and become more specialized. Some areas shrink slightly as neural networks become more efficient, helping mothers become exquisitely tuned to their baby’s needs. In other words, what people casually call “pregnancy brain” isn’t a malfunction, it may actually be the brain rewiring itself for one of the most complex caregiving jobs on the planet.

Women’s immune systems also tend to be more robust than men’s. Evolutionarily speaking, this makes sense: the survival of a mother was essential for the survival of her children. But this advantage comes with a tradeoff. Women are significantly more likely to experience autoimmune diseases such as lupus, rheumatoid arthritis, and multiple sclerosis—conditions where the immune system becomes a little too enthusiastic and starts attacking the body itself.

Interestingly, these same biological differences may also help explain another phenomenon researchers have observed across many populations: women tend to survive famine and extreme food scarcity better than men. Women’s bodies are generally more efficient at storing and managing fat reserves and regulating metabolism during long periods of stress. Evolutionarily, this ability likely helped protect both mothers and the developing babies they carried.

And then there’s menopause, one of the most unusual biological features in the animal kingdom, and until recently, one of the most under researched and undermanaged biological phenomena.  Human females are among the very few mammals who live decades beyond their reproductive years. Scientists still debate exactly why, but one popular explanation is called the “grandmother hypothesis.” Communities and families tend to thrive when older women share knowledge, help care for grandchildren, and support younger mothers.

In other words, evolution may have decided that grandmothers are a competitive advantage.

Unfortunately, while women’s bodies played such a central role in shaping humanity, modern medicine didn’t always treat them that way.

For decades, the male body was considered the “default” human body in research. Women were frequently excluded from clinical trials because hormonal cycles were considered inconvenient variables.

The result? Some important gaps in knowledge.

Heart attacks, for example, often present differently in women than in men. Instead of the classic crushing chest pain many of us associate with heart attacks, women may experience symptoms like nausea, fatigue, back pain, or shortness of breath. Because research historically focused on men, these differences weren’t widely understood for years.

Medication dosing has also sometimes been based primarily on male physiology, despite clear differences in body composition, hormones, and metabolism.

Even pain itself is often taken less seriously in women in clinical settings. Many conditions that disproportionately affect women—endometriosis, autoimmune disorders, and menopause-related symptoms—have historically been minimized, misunderstood, or dismissed.

Thankfully, that is beginning to change.

As someone who works with the body every day, I’ve learned something important from my female patients over the years: listen carefully.

Many women arrive with a deep awareness of their bodies, often because they’ve had to advocate for themselves in medical settings. Their experiences have pushed me to read more, ask better questions, and understand the structural and physiological differences that deserve thoughtful care.

Quite honestly, many of my best lessons as a practitioner have come from listening to the women who walk through my door.

So during National Women’s Month, I want to acknowledge something simple: the female body is not just a variation of the male body. It is an extraordinary biological system that has shaped the evolution of our entire species.

And we’re still learning from it.