Observing Biological Sex
Humans are able to differentiate between men and women regardless of culture or race by using a combination of visual cues, such as facial structure, body shape, and secondary sexual characteristics.
We are sexually dimorphic, meaning that we naturally exhibit different morphological characteristics in various parts of the anatomy, even in organs that are not directly part of the reproductive system, depending our biological sex. These differences are typically most pronounced after puberty, and we have evolved to be able to easily recognize them in others simply by perceiving them with our unaided eyes.
The brain processes these visual cues through a neuronal network of image recognition, which uses patterns of anatomy that have been evolved to be recognized, in any fully clothed adult person who is not actively attempting to conceal them. Although there is no single definitive trait that allows us to conclude if a face is male or female, the brain is able to process and integrate a multitude of variables to make this determination.
Here is a list of a few visible variables that on average, are different between men’s and women’s, faces:
Facial structure: Men and women typically have different facial structures, such as jawline and brow ridge.
Facial hair: Men are more likely to have facial hair, such as beards or mustaches.
Skin texture: Men's skin is generally thicker and oilier than women's.
Lip size: Men's lips are typically thinner than women's.
Hair: Men's hair is typically thicker and coarser than women's.
Adam's apple: The protrusion at the front of the neck is much more visible in men.
Forehead: Men's forehead is typically larger than women's.
Cheeks: Men's cheeks are typically more prominent than women's.
Nose: Men's nose is typically larger and wider than women's.
Eye shape: Men's eyes are typically more almond-shaped than women's.
Eyebrow shape: Men's eyebrows are typically thicker and straighter than women's.
Ear shape: Men's ears are typically larger than women's.
Ear position: Men's ears are typically positioned lower on the head than women's.
Hairline: Men's hairline is typically higher and recedes further than women's.
Facial symmetry: men's faces tend to have less symmetry than women's.
Facial delicacy: women's faces tend to have more roundness and softness in the features.
Neck size: men's necks tend to be thicker and more muscular than women's.
Facial expression: men tend to have more serious or neutral facial expressions than women.
Hair color: men tend to have darker hair than women.
Brow ridge: Men have a more prominent brow ridge above their eyes than women.
Cheekbones: Men typically have flatter cheekbones than women.
Hair distribution: Men tend to have hair growth on a larger area of their face than women.
Overall facial proportions: Men's faces are generally longer and wider than women's.
Here is a list of a few visible variables that on average, are different between men’s and women’s, fully clothed bodies:
Men tend to have a larger bone structure and a more muscular build compared to women.
Women typically have a higher percentage of body fat and a more curvy figure.
Women typically have wider hips, a narrower waist, and larger breasts than men.
Men typically have more body hair, including facial hair, chest hair, and arm hair than women.
Men typically have larger hands and feet than women.
Here is a list of a few non visible variables that on average, are different between men’s and women’s, fully clothed bodies:
Men tend to have a deeper, more resonant voice, while women tend to have a higher-pitched voice.
Men typically have a stronger body odor than women.
Research has shown that babies as young as 6 months old can begin to differentiate between men and women. Studies have found that infants at this age can recognize the difference between male and female faces, and can also match voices to the corresponding faces.