See How Twin Boys Became Brother and Sister

Twins Jonas and Nicole Maines were born as identical twin boys. But when Nicole—born as Wyatt—was 2 years old, she knew that though she was born with the male gender, she was truly a female.

“Whenever we were playing dress up she always wanted to be the girl,” Jonas remembers in an interview with PEOPLE. “She always played with the dolls.” Jonas always went along with it. “I never questioned it,” he said.

Pulitzer-Prize winner Amy Ellis Nutt’s chronicles Jonas and Nicole’s story in her latest book Becoming Nicole: The Transformation of a an American Family, out October 20.

Read more at People.com