A Yorkshire Police force is one of six in the country which is allowing convicted male rapists to be recorded as female if they no longer want to identify with their sex at birth.
South Yorkshire Police has adopted the practice which allocates sex offenders with a different gender identity on their official database which is used by the Home Office.
Other forces across the country include Durham, Kent, Norfolk, Suffolk and the British Transport Police, according to a Freedom of Information request compiled by women's rights group Fair Play for Women.
Speaking to the Sunday Times, Fair Play for Women Director Nicola Williams said: "You can't get much more of a male crime than rape.
"It would be highly offensive to a woman who was raped to have it written down that her attacker was a female when clearly that was a male with his genitals."
In a statement, South Yorkshire Police said: 'We will accept the details that an individual provides us and treat them according[ly]."
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Responding to questions about males sex offenders identifying as females, Thames Valley Police confirmed they only be referred to as females in their system.
Dorset, Dyfed-Powys and North Wales police confirmed the same policy, as did Devon and Cornwall, although it also records the person's previous identity.
The National Police Chiefs' Council said: "How gender is recorded is a matter for each individual force. However, as a general rule we will accept the details that an individual provides us and treat them accordingly."