She was born a man, but had a sex change. Now she wants to marry her boyfriend. But the government says she can't, so she's going to court. The case - a first for Hong Kong - which a judge will begin hearing tomorrow, looks set to expose contradictions in the way the administration treats people who change their sex. The woman, who is Hong Kong Chinese and in her twenties, underwent sex-change surgery at a public hospital. She has had her sex changed on her identity card. But last year the Registrar of Marriages ruled she could not marry her boyfriend. The decision to deny her the right to marry was made because her birth certificate - which cannot be changed under Hong Kong law - still shows her to be a man. In effect, the only person she can legally marry is a woman. A person with knowledge of the case said the government was concerned that granting her the right to marry might lead to legal complications and signal a move along the road to same-sex marriages, which are not recognised in Hong Kong. To fight the case against the woman, who under an anonymity order can only be identified as 'W', the government has drafted in a Queen's Counsel from London, Monica Carss-Frisk. She will lead a team of local lawyers. Although the use of London 'silks' - as QCs are commonly called - is not uncommon in Hong Kong, Carss-Frisk had to be specially admitted to the Hong Kong Bar in order for her to argue the case in the Court of First Instance. According to legal insiders with a knowledge of QC fees, they can command six-figure sums for their services and are normally admitted because no one of sufficient expertise is available locally. The legal team for 'W', led by Philip Dykes SC, will argue that the law as it stands breaches their client's rights under the Basic Law and Bill of Rights. The woman's lawyer, Mike Vidler, said: 'On the one hand, the government has recognised the rights of transgender people by having in place for years a system of gender support and the provision of sex reassignment surgery. 'Yet on the other, they want to stop a person who has been living as a woman for several years - with their help and assistance - enjoying the same rights as other women. 'This is not a back-door step towards same-sex marriage, it is simply a case of allowing a couple to express their love for each other and live life together as a married couple.' Vidler said his client underwent sex reassignment surgery in a public hospital over a five-year period. As well as having her identity card changed to state that she is female, other documents, such as certificates issued by schools, have also been amended to reflect her new sex. A spokeswoman for the Department of Justice said the hearing was set to run for two days and confirmed that Carss-Frisk had been admitted to lead its team of local barristers. 'This is the first case to reach the High Court which involves a transsexual seeking to marry in the acquired gender,' she said.