Lawyer David Coombs has revealed that Manning had known for a long time she would make such a statement, but “she wanted, essentially, for the media surrounding the trial to dissipate”.
Manning, 25, did not want people to think the statement was insincere.
“People might think it was an effort to get further attention,” Coombs said.
Manning was sentenced last week to 35 years in prison for leaking thousands of pages of classified military and diplomatic material to the anti-secrecy website WikiLeaks. The earliest the soldier could be released on parole is 2020.
Coombs said he and Manning knew the US Army might not provide hormone treatment, but they were hoping the military prison at Fort Leavenworth would allow it as Manning had been diagnosed with gender identity disorder by a military psychiatrist who testified at the trial.
It wasn’t until they read a Courthouse News Service story that Manning decided to make the announcement. The story quoted prison spokeswoman Kimberly Lewis saying the prison would not provide hormone therapy. It was published on 20 August, the day before Manning was sentenced.
“It was Chelsea’s intent to do this all along,” Coombs said. “It was only after Fort Leavenworth had said that they would not provide any sort of medical treatment that we decided not to wait.”
Coombs said he hoped the military prison will “do the right thing” so Manning will not have to sue in military or civilian court to gain access to treatment.
Coombs said at this point, Manning does not want sex-reassignment surgery and expects to be kept with men in prison. The Fort Leavenworth prison is all-male.
Coombs said he had seen people online objecting to US taxpayer-funded hormone therapy and said Manning will pay for it.
Hormone therapy, which typically involves high doses of oestrogen to promote breast development and other female characteristics, can help Manning, Coombs said.
“It’s just to be comfortable in her own skin,” Coombs said. He described it as similar to ensuring someone with high blood pressure gets medication.
Coombs also said on his blog that Manning chose Elizabeth as her middle name, replacing Edward. He posted Manning’s statement about her identity change, which was first reported by the American network NBC last Thursday.
Coombs said Manning knows there is the potential for confusion with the name change. The lawyer said Manning expects to be referred to as Bradley when it has to do with events prior to sentencing, the appeal of the court-martial and the request for a presidential pardon. Prison mail must also be addressed to Bradley Manning.
“There’s a realisation that most people know her as Bradley,” Coombs said. “Chelsea is a realist and understands.”
Coombs also said the Bradley Manning Support Network is changing its name to the Private Manning Support Network. It has raised more than $1 million (about £640,000) and is paying Manning’s legal expenses.