NIPPLES serve a very clear biological purpose – to feed babies.
But the reason why men also have them remains unclear. 知っておくべきことはすべてここにあります.
Why do men have nipples?
People often wonder why men have nipples, but the answer is very simple.
Men have nipples because of the way that human foetuses develop in the womb.
Male nipples are often considered vestigial, or functionless due to evolution.
しかしながら, the nipples contain a huge network of nerves meaning they function as a secondary sex characteristic of men, like an Adam’s apple or facial hair.
During the first few weeks of a pregnancy, the male and female embryos follow the same path.
In those early stages, there are no biological differences between the sexes.
It’s only when the Y chromosome takes hold in the seventh week of pregnancy that the foetus is characterised as male.
At this stage the nipples have already formed and secured their place!
Female foetuses go through different changes that eventually lead to the development of breasts.
Can men breastfeed?
Some dads may wish they could breastfeed to give the mother of their child a break, there are even fake plastic breasts with realistic features to simulate the real thing.
There are even kits that help men develop milk ducts so they can breastfeed – they just have to take a cocktail of hormones beforehand.
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But it turns out it is possible without gadgets or taking medication.
Milk is produced inside cells in the inner lining of the breast tissue (known as alveoli).
Milk production is triggered when there are sufficient levels of the hormone prolactin.
Prolactin is mostly produced by the pituitary gland, though it can also be produced by the prostate or the uterine wall.
Men and women both produce prolactin, but in very different amounts – prolactin is metabolised by the 肝臓.
So when there are issues with the liver, it can lead to an overproduction of certain proteins like prolactin which can lead to lactation.
It’s thought that this happened during 第二次世界大戦, when male prisoners of war began lactating after months of starvation.
It’s not just adults, while uncommon it turns out that newborn babies of both sexes can produce milk.
The phenomena is known as witches milk.
The name derives from an idea from well over 300 years ago during the 17th century, where people believed that witches would come to steal the milk and use it for magic.
So infants were “milked” so that their milk couldn’t be stolen.
The condition tends to go away after two months.
Can men get pregnant?
まれです, but it is possible for a man who used to be a woman to get pregnant naturally.
Testosterone suppresses egg production and release, essentially putting the reproductive organs into hibernation, so when someone stops taking it, they can regain some of those biological functions.
The embryo can then be fertilised and transferred to a surrogate or carried to term.
That’s what Hayden Cross, the first British man to get pregnant やりました.
Cross made headlines around the world when he announced he was pregnant back in 2017, with an anonymous sperm donor.
The first man to get pregnant in the world was Thomas Beatie, 誰が 2007 conceived a child through artificial insemination – he has since given birth to two other children.