Lori and George Schappell were joined at the skull with separate bodies and lived on their own since the age of 24

The world’s oldest living conjoined twins have died at the age of 62 in their native Pennsylvania.

Lori and George Schappell died on 7 April at the hospital of the University of Pennsylvania in Philadelphia, according to an obituary. A cause of death was not disclosed.

The Schappell twins were born on 18 September 1961 in Reading, in southern Pennsylvania. They were joined at the skull with separate bodies, sharing 30% of their brain and essential blood vessels.

George had spina bifida and used a mobility device. Lori pushed and steered George’s wheeled stool so the two could move around.

The twins represented the rarest form of conjoined twinning, which affects only 2% to 6% of conjoined twins, NBC Today reported.

George transitioned in 2007, with the Schappells becoming the first same-sex conjoined twins to identify as different genders, Guinness World Records reported.

George discussed his decision to come out with the Sun newspaper in 2011 when the siblings visited London to celebrate their 50th birthday and vowed to “continue living life to the full”.

He said: “I have known from a very young age that I should have been a boy.”

He added: “It was so tough, but I was getting older and I simply didn’t want to live a lie. I knew I had to live my life the way I wanted.”

The Schappells graduated from the Hiram G Andrews Center, a technical institute in Elim, Pennsylvania. They both worked for Reading hospital for a number of years.

The Schappells had distinct hobbies and interests.

George performed as a country music singer, traveling to several countries including Germany and Japan, according to Guinness World Records. Meanwhile, Lori was a lauded tenpin bowler.

The siblings lived on their own since the age of 24. They previously lived in an institution for people with intellectual impairments, despite not being mentally disabled, following a court order, New York Magazine reported.

Later, the two shared a two-bedroom apartment. Each sibling had their own room, alternating which room they would sleep in each night.

The Schappells said that, despite being conjoined, they were able to have privacy in the shared apartment.

“Just because we cannot get up and walk away from each other, doesn’t mean we cannot have solitude from other people or ourselves,” Lori said in a 1997 documentary.

For example, when George needed to rehearse his country music, the pair would go to his room, where Lori would remain quiet and allow George to practice.

While some conjoined twins have opted to be separated via surgery, such procedures weren’t available when the Schappells were born.

The twins also rejected the idea of separation.

“Would we be separated? Absolutely not,” George said in a 1997 documentary. “My theory is: why fix what is not broken?”

“I don’t believe in separation,” Lori said to the Los Angeles Times in a 2002 interview.