Men tend to have larger and more prominent Adam’s apples compared to women. An Adam’s apple is the lump or protrusion in the front of the neck formed by the thyroid cartilage surrounding the larynx. There are several biological factors that contribute to men having larger Adam’s apples than women.
The larynx grows more in men during puberty
The main reason men’s Adam’s apples are larger is because the larynx (voice box) grows much more in boys during puberty. At puberty, the larynx grows prominent in size in males but not in females. This growth is triggered by the increased levels of testosterone in males at puberty.
Before puberty, there is little difference in larynx size between boys and girls. But during puberty, the male larynx grows both longer and wider. The larynx descends lower in the neck as it enlarges, forming the Adam’s apple protrusion.
Testosterone causes larynx growth
It is the increased levels of testosterone, the male sex hormone, during puberty that drives growth of the larynx in boys. Testosterone causes cell proliferation and enlargement of the cartilage and muscles of the larynx. The thyroid cartilage that surrounds the larynx enlarges outwards, forming the protrusion of the Adam’s apple.
Estrogen limits larynx growth in females
In contrast, puberty in females is associated with rising levels of estrogen, the main female sex hormone. Estrogen actually limits the growth of the larynx in girls during puberty. The female larynx still grows slightly but not to the same prominent extent as in males under the influence of testosterone.
So while testosterone drives laryngeal growth in males, estrogen suppresses this growth in females. This hormone difference during puberty results in the much smaller or non-visible Adam’s apple in women compared to men.
The male larynx serves additional functions
Apart from the hormonal influence, the larger male larynx also serves additional functions not present in women. The key function is to produce and modulate the lower-pitched male voice. The longer vocal cords and enlarged resonance chambers in the male larynx help produce a deeper voice.
Having a protruding Adam’s apple is a side effect of the enlarged laryngeal structure needed to create the male voice. Women do not require such vocal anatomy so their larynxes remain smaller without an Adam’s apple.
Genetic and ethnic factors
There are also some genetic and ethnic factors that can influence Adam’s apple size in men:
- Men from some ethnic backgrounds, such as people of Middle Eastern and Mediterranean descent, tend to have larger, more prominent Adam’s apples.
- The SIZE1 gene is linked to larynx size, with mutations associated with a larger Adam’s apple in males.
- Rare conditions like Klinefelter syndrome (XXY chromosomes) in men can also result in a larger than average Adam’s apple.
But while genetic and ethnic factors play a role, the fundamental reason remains the effects of testosterone on the male larynx during puberty.
Changes with age
The prominence of the Adam’s apple changes over a man’s lifetime:
- During puberty, the Adam’s apple grows quickly in size over a few years.
- It remains stable in adulthood but may enlarge slightly due to further testosterone exposure.
- In older age, the Adam’s apple stretches as the larynx descends lower in the neck, so it remains visible but protrudes less.
In women, the Adam’s apple remains small and is often barely visible throughout life. But in some older women, the thyroid cartilage may protrude slightly due to larynx changes.
Conclusion
The Adam’s apple is more prominent and obvious in males compared to females predominantly due to the effects of the sex hormones testosterone and estrogen on larynx growth. The male larynx enlarges significantly during adolescence under the influence of rising testosterone levels, creating the protrusion of cartilage known as the Adam’s apple. In contrast, estrogen in females during puberty suppresses larynx growth, resulting in a small or invisible Adam’s apple. Genetic and ethnic factors can also play a role in Adam’s apple size, but pubertal hormone exposure remains the key determinant of this gender difference.