Now, 22 years later, the twins have certainly proved them wrong.

The girls have recently graduated from university, are about to travel to Europe with friends and are on the hunt for their first job.

They are also up-and-coming reality TV stars, with US network TLC offering them their own TV show called “Abby and Brittany”.

The girls, who share one body with each controlling one side, first captured the world’s attention when they appeared on the The Oprah Winfrey Show in 1996.

Since then they have lived a quiet life with their family, including their 20-year-old brother Cody and 18-year-old sister Morgan, in Minnesota. When the pair turned 16, they agreed to appear in a documentary for TLC, in which they proved they really are individuals.

Like many other sets of twins, the girls have very different personalities. Abigail is feisty and stubborn, while Brittany is the joker of the family.

"Believe me, we are totally different people," Brittney said during the documentary.

Throughout their life, the pair have continued to stun doctors with their incredible co-ordination and team work, which they use every day for everything from getting dressed and doing each other’s hair to playing the piano and driving where they each control one arm to steer the car.

The girls are believed to be one of only a few sets of dicephalus twins in history to survive infancy. Parents Patty and Mike say they have never even considered having them separated.

At the time Patty was pregnant with the girls she didn’t even realise she was having twins, now she can’t imagine life without them.

“From the first time we saw them, we thought they were beautiful,” she said.

“I kissed Abigail and then Brittany and gave them a hug. It's like that every time I pick them up from school, two kisses and one hug for the most beautiful children in the world.”

“Abbey and Brittney” will premiere on TLC in the US on August 28.

Video: See Abigail and Brittany in the video player above.