The 41-year-old writer, activist and reality-TV star, was born a girl to Sonny Bono and Cher. He filed a petition to change his name and gender last week.
Bono's doctor filed a declaration with the court indicating he performed a gender-change operation last year.
Formerly called Chastity, Bono has called the gender change "the best decision I've ever made."
The filing was first reported by celebrity Web site TMZ.com.
A hearing on the petition is scheduled for May 6 in Santa Monica, Calif.
AP file photo