Transsexual persons are those who have changed from one sex to another. Normally transsexuals change their gender by undergoing a sex reassignment medical treatment and surgery. They can then apply to change to a new identity card (HKID card) with the newly acquired gender.

According to section 40 of the Marriage Ordinance , marriage involves a voluntary union for life of one man and one woman to the exclusion of all others.

The Court of Final Appeal decision in W v Registrar of Marriages recognize a transsexual’s right to marriage. It was declared that the meaning of “woman” and “female” includes a post-operation male-to-female transsexual person whose gender has been certified by an appropriate medical authority as having changed after sex reassignment surgery. Accordingly, the Court held that under the law “W” is entitled to be included as “a woman” under the relevant provisions of the Marriage Ordinance, and therefore is eligible to marry a man.

Further, the Court of Final Appeal held in Q & Tse Henry Edward v Commissioner of Registration that the underlying policy of the Commissioner of Registration requiring a full sex reassignment surgery (which involves a highly invasive surgery to remove the uterus and ovaries and construct an artificial penis for the female to male transgender persons) before amending the gender markers on their HKID cards, was unconstitutional. In other words, the completion of full sex reassignment surgery is not a necessary condition for amending the gender markers on transgender persons’ HKID cards. The appellants in that case have been medically certified that additional surgical procedures are not needed, the surgery carries certain post-operative risks and possible complications, and is medically unnecessary for many transgender persons, including the appellants.