A woman who was told she was a "late developer" during puberty was actually born with a rare condition which meant that she only grew one breast.
Becca Butcher, 23, from Barnsley, South Yorkshire, suffers from Poland Syndrome, which means one breast is significantly smaller than the other as her right one is a D cup, while the left is an A cup.
Despite suffering horrible teasing at school, Butcher turned down breast surgery on the NHS, and has instead learnt to love her body as it is.
Now she hopes to inspire other women to speak up about the rare condition, which is believed to affect between one in 20,000 to one in 100,000.
Butcher says she first starting noticing the difference in her breasts when she hit puberty.
“I noticed that one of my breasts was bigger and might have needed a bra, but I thought there was no point getting one until the other one has grown," she explains.
"A friend said to me once: 'You know one of your boobs is bigger than the other?'
"Eventually I had to start wearing bras, but I bought bras that fit the smaller one to push it back.”
Having repeatedly visited doctors during her teenage years, Butcher was told not to worry as she had not yet finished puberty, with her GP believing her left breast would eventually grow.
But as Butcher's right breast continued to go up cup sizes, she began to worry.
Eventually she searched online and came across the little-known condition.
"I went to the doctors aged 15 or 16 and they said it's just normal, don't worry, it's nothing to worry about, I was just a late developer and I had not finished puberty yet," she says.
"I would go every six months or so and I thought I would wake up one day and magically have two boobs.
"I searched 'one boob' online and it came up with Poland Syndrome.
"It was mainly pictures of men as it is more common in men, but you could tell they had a difference in their chest.
"I went back to the doctor and told them I had come across Poland Syndrome and he said he had never heard of it.”
Watch: Little boy's weight doubles due to rare syndrome.
Butcher says that because so few doctors have heard about it, the syndrome can often go undiagnosed.
She was offered surgery on the NHS to bring her left breast to the same size as her right one, but she refused as she did not believe she needed to be “fixed”.
"I didn't want the boob job, I told them ‘I don't want surgery, I want information about why I am the way I am'," the content creator explains.
"I didn't want to change it, I wanted to know how to live with it. It's like I'm broken and need fixing.”
Read more: We've been putting our bras on wrong
Butcher began sharing her experiences online and has now developed a community of other women suffering from the syndrome.
“I realised that there must be other young girls feeling like this," she says.
"And thought that if I spoke out, they will know they're not the only one.
"I made a YouTube video as I didn't want other women to feel like they were the only one going through it.
"Over the past couple of years I get a new message every week from people who have it or who have a kid who has it asking for advice.
"A lot of women tell me they have never had a boyfriend because they are so scared of someone seeing their boobs.
"I tell them the right person will love you for you. If somebody doesn't love you for your boobs, they're not the person for you. If they care more about your boobs than your feelings then they're not nice people.”
Butcher, who has been with her boyfriend, Kyle Officer, for the last two years, added: "No guy has ever had a problem with it or been put off by it.
“I tell men up front about it. I say I have a chest deformity that means the muscle underneath my chest wall didn't develop properly at birth, that's just how it is.”
Butcher believes more awareness of the condition would improve the lives of people with the syndrome.
“Poland Syndrome doesn’t affect your physical health but it affects your mental health," she explains.
“Simple things like buying clothes can be hard. You can see what clothes would look like on a girl with big boobs, a girl with small boobs, but you can’t see what it would look like on a girl with one of each.
“When I was younger I used to wear turtlenecks and cover it up. But now I am happy and fine to wear what I want.
“I have a WhatsApp group of more than 100 women now who message each other and support each other.
“But it’s a bit of a vicious circle. People don’t go to the doctors with it, so the doctors don’t know what it is, so it doesn’t get diagnosed when they come across it.
“That is what needs to change.”
What is Poland Syndrome?
According to Great Ormond Street Hospital (GOSH) Poland or Poland's syndrome is a very rare condition that is characterised by webbing of the fingers and of underdevelopment of chest muscle.
It usually affects one side of the body.
Other symptoms can include shorter than usual fingers, and problems with the digestive tract.
The condition is more prevalent in men with famous sufferers including Jeremy Beadle and Fernando Alonso.
While it is not known exactly what causes this condition. The most popular theory is that it could be linked to a problem with blood supply around the end of the second month of gestation.
For more from Becca Butcher follow her on Instagram.
Additional reporting SWNS.