Imprisoned transgender US soldier Chelsea Manning is taking issue with the military’s plan to allow trans troops to serve openly.

While Manning called US Defense Secretary Ash Carter’s official lifting the ban last week ‘a relief,’ she is against a requirement that new recruits be ‘stable in their identified gender for 18 months, as certified by their doctor, before they can enter the military.’

‘We don’t need the military to be the gatekeeper of our gender expression and identity,’ Manning writes in a column published by The Guardian. ‘We should be able to define ourselves.

‘By setting so many caveats, time lines, standards, and training, the military is making this far, far, more complicated and bureaucratic than it needs to be. The simple reality is that we are who we say we are.’

Manning is currently serving a 35-year military prison sentence for leaking secrets to WikiLeaks and is ‘deeply concerned’ the impact of this change won’t penetrate the prison walls.

‘What does it mean that the military will recognize our gender, unless and until we are arrested, and then what? This core identity is then stripped away and our birth assigned sex is imposed on us?’

Manning has had her struggles with transitioning while in prison.

Last September, she was ordered to cut her hair by authorities at US Disciplinary Barracks at Fort Leavenworth, Kansas.

Manning later wrote that she was left feeling ‘humiliated, hurt and rejected.’

Already, an estimated 15,500 transgender people have been serving in silence in the US military services and reserves, according to OutServe-SLDN.

The Pentagon will create training handbook, medical protocol and ‘guidance for changing a service member’s gender in the Defense Eligibility Enrollment System’ by 1 October.

The change officially came last week, nearly five years after the end of Don’t Ask, Don’t Tell which had prevented gays and lesbians from serving openly.