It's true that sometimes people end up with names their parents never dreamed of when naming their precious bundle of joy.
There are times a pet name sticks, and the much-considered "perfect name" the parents-to-be spent months searching for is relegated solely to the birth certificate.
A frustrated mum has aired her frustration on Reddit, saying that the baby name they chose for their fourth child - Scarlett - has been dumped by family in favour of the pet name her brother gave her. And she isn't happy about it.
She explains in a post, "My youngest of four is 19 months old. Her name is Scarlett but when she was a baby, my now three-year-old started calling her Sissy because she is his sister and he struggled with saying Scarlett."
What started out as a cute pet name, has now become the name people use.
"He can say Scarlett now but the nickname stuck. My older two call her Sissy all the time and family does as well," she writes.
She says she doesn't mind, but the post indicates otherwise.
"I don't mind. She responds to her real name and I am not worried about her learning to tell people her name is Scarlett, but damn, nine months of searching through every name website just for everyone to call her a nickname for sister? Really?"
Commenters responded with their own take on it. It seems many sisters are referred to as "Sissy."
"My baby brother still calls me Sissy... he's 27. He didn't know my name wasn't Sissy until he was like 10 and it blew his mind," wrote one person.
"This is so sweet. I have a 19 month old Sonny," wrote another, while another responded, "My sister struggled to say my name, and it ended up turning into Mimi, which she called me for a while. Now she has a son, and everyone taught him that I'm Mimi, and he's almost six and doesn't believe me when I say my real name."
It turns out Sissy and Mimi are quite normal names in the scheme of things, if this next comment is anything to go by.
"I had a friend who went through a 'Super Grover' phase. He got separated from his parents at an amusement park and security had to page the parents of 'Super Grover' since that's all he would give them as a name. I mean, it worked though. They knew it was their kid."
Many conveyed that nicknames are just part of life and completely out of anyone's control.
"Nicknames just emerge. Nothing can be done," quipped one person, while another agreed, "Exactly! A friend of mine has an uncle that they call 'boy.' When he got married, everyone called his wife 'girl'. She got nicknamed by association."
And it seems that people called Scarlett attract a lot of different nicknames - mostly Scar or Scarface Claw, but also this adorable one.
"My kids are friends with a Scarlett who goes exclusively by 'Sharky.' Mum, Dad, teachers, everyone just calls her Sharky and it's adorable."
There are hundreds of replies with similar stories of grown men still called Boo, Bug, Sugar Bear and Bubby, and adult professional women who still go by Piffy, Lala and Goon (yes Goon) with their families and friends.
In the light of these some suggest Sissy is perfectly wonderful.
"The nickname will fade eventually," writes one person. "Once she enters the adult world she will appreciate [having the name Scarlett]."