Men and Women’s Different Biology Supports Their Different Roles

“Can men get pregnant?” It’s a simple question that any person should immediately know the answer to. However, when Senator Josh Hawley from Missouri asked that question of ob-gyn, Dr. Nisha Verma, she hedged on the answer.1 She said she treats people with different identities (meaning gender identities) and did not directly answer him. Senator Hawley further clarified his question asking her to answer based on science and stated that he was referring to biological men. But each of the 12 times he posed the question, “Can men get pregnant?,” Dr. Verma refused to give a yes/no answer. How have we gotten to the place where a physician that specializes in women’s reproductive health is NOT willing to assert the biological reality that no, men cannot get pregnant, only women can?

There is a simple answer. People deny God’s authoritative Word. They deny the creation account in Genesis where God created male and female in his image (Genesis 1:26–27). They deny that God joined Adam and Eve in marriage and told them to be fruitful and multiply and fill the earth (Genesis 1:28, 2:24). They deny that God gave unique roles to men and women within marriage (Genesis 2:18). They deny that Adam named his wife Eve “because she was the mother of all living” (Genesis 3:20). They deny Jesus’ confirmation of the creation of male and female and God’s design for marriage (Matthew 19:4–6). As a result of that denial, they are willing to deny the very biological reality that God created. “They exchanged the truth about God for a lie and worshiped and served the creature rather than the Creator” (Romans 1:25).

As a result of that denial, they are willing to deny the very biological reality that God created.

In Part 1, I discussed biblically how men and women are created equally in God’s image but display that image in unique ways. I showed genetically that we are unique from our sex chromosomes to our ribosomes and even our gene activity. I also related how those differences might help us fulfill the unique functions that God designed for men and women.

In Part 2, I want to observe the outcomes of those genetic differences as we look at some of the anatomical and physiological distinctions between men and women. We will once again see that God’s design for men and women is indeed purposeful.

The primary reason for all these anatomical and physiological differences is the types and levels of sex hormones (e.g., testosterone and estrogen). Those hormone levels are controlled by the primary sex organs (e.g., testes and ovaries), and their formation is controlled by the sex chromosomes, with males being XY and females being XX. These differences don’t make one sex superior to the other, just different and unique as designed by God.

Skeletal Differences

Males have larger bones and higher bone mass than women.2 And the structure and shape of the pelvis is decidedly different, with the female pelvis being wider and the inlets and outlets larger in diameter than the male pelvis.3 This is so women can carry and give birth to children (a very important reason why men cannot get pregnant!).

Muscle and Fat Differences

Male hormones promote muscle development and give men higher muscle mass than women.4 In addition, men tend to have more fast-twitch muscle fibers, making them better at sports that require bursts of energy.5 This is why men’s times for running the 100-yard dash will always be faster than that of women.

Female hormones are more likely to promote fat storage, so women have higher body fat than men.6 They tend to be better at sports that require endurance because fat is a good energy reserve. Now before all the ladies reading this get depressed by this reality, fat is important for fertility in women. This can sometimes be seen in women that are elite athletes. They have minimal body fat and irregular menstrual cycles, which can result in infertility.7

Fat and muscle differences are also why women tend to feel colder than men. Men have greater muscle mass that generates more heat (a by-product of cellular metabolism), while fat causes greater distance between the skin and blood vessels, causing women to feel colder.

Lung and Heart Differences

Males have 10–12% higher lung volume,8 and the width of the central airways (e.g., trachea, main bronchi) is 26–35% higher than in women.9 The female heart is 26% smaller in mass and the cardiac output (amount of blood pumped out each minute) is 22% smaller than in a male heart.10

These anatomical differences are why men and women should have their own separate sports and not compete against one another. Men have a distinct advantage over women due to their larger bone and muscle mass, larger lung volume, and larger hearts. One study stated, “7650 adult males and 394 youth males have run best times faster than the current female world record in the 100 m dash (10.49 seconds).”11 This is why transgender women (biological males claiming female identity) should not be allowed to participate in women’s sports. No amount of estrogen and/or blocking testosterone will fundamentally change a male’s anatomy!

Brain Differences

Overall, males are generally larger and have larger brain volume than females, and parts of the brain like the cerebrum and cerebellum also tend to be larger.12 However, within specific regions of the brain, women can have larger volume or tissue density.13 A 2024 study14 successfully used AI to analyze brains for differences related to sex, “This [the research] is a very strong piece of evidence that sex is a robust determinant of human brain organization.”15 What remains a mystery is how to relate those physical differences in the brain to mental and behavioral differences.

Women have more connections between their brain hemispheres in the region known as the corpus callosum, whereas men tend to have more connections within each hemisphere.16 Some believe this could be the basis for women’s “intuition,” multitasking, and the ability to integrate information from multiple sources. It could also be the basis for men being credited with more straightforward thinking, quick reaction times, and being less distractable. This aligns well with the common functions that men and women are designed for. When my daughter was young, I told her I have “mom vision.” It meant I can be doing something unrelated to her but still know what she’s doing! It’s valuable for men to be focused and react quickly especially in times of war or protecting loved ones.

Other sex differences in the brain may result in the fact that women and men have different aptitudes.17^, 18 Below is a short list of some of those for each sex.

Women	Men
Verbal and writing ability Reading comprehension Fine-motor coordination Long-term and visual memory Finer discrimination of color	Visuospatial skills Tracking moving objects Aiming projectiles Working memory

This is not to say that men can’t be good authors or women can’t be good sharpshooters. These aptitudes are on a spectrum, but there’s no denying that women and men preferentially excel at different things and that it’s part of God’s good design.

Some might argue that these differences in abilities are not “nature” but “nurture” because parents give their children certain toys and encourage certain behaviors. This would cause the development of sex-specific aptitudes and behaviors. However, multiple studies have shown these sex-specific traits are present at very young ages in children. For example, “Boys and girls 9 to 17 months old—an age when children show few if any signs of recognizing either their own or other children’s sex—nonetheless show marked differences in their preference for stereotypically male versus stereotypically female toys.”19 In other words, the girls liked the dolls and cookware and the boys liked the cars and balls.20 So it’s nature in the sense that this is part of how God purposefully designed women and men differently!

Conclusion

In March 2022, Supreme Court nominee (now justice) Ketanji Brown Jackson was asked a simple question by Tennessee Senator Marsha Blackburn, “Can you provide a definition for the word woman?”21 Brown Jackson’s reply, “No, I can’t. Not in this context, I’m not a biologist.” No one needs a degree in biology to be able to define a woman! Yet this is what happens when people deny biblical authority—they start denying biological reality to serve the creature and not the Creator (Romans 1:25).

Praise God that he created men and women different! I love how this author put it,

Males and females are differently programmed by nature, and it must be respected. Even though we as males and females are not the same, we would like to emphasize that we are still equal and together form a worthy colorful continuum.22

God purposefully designed men and women for the unique functions he prepared for us.

This author is likely an evolutionist, so I don’t agree that nature programmed us. Instead, God purposefully designed men and women for the unique functions he prepared for us. We see this from our DNA to our cells to our organs to our aptitudes. Men and women are equally made in God’s image, but we display that image uniquely as part of a “worthy colorful continuum.” Let’s embrace those differences and treat each other with respect and care as God’s image bearers.