Gender, defined by the World Health Organisation as the socially constructed characteristics of women and men, is not to be confused with sex.
Gender is performed through ways such as mannerisms and attire, in accordance with gender roles, usually either masculine or feminine, prescribed by society.
Sex, however, is determined biologically by chromosomes and reproductive organs.
Apart from the conventional categories of male and female, many may be identified as transgender, bi-gender - or even their gender may be questioned.
As with many places, gender is a socially and judicially contested concept in Malaysia.
In November 2014, three transgender women applied for judicial review under Section 66 of the Negeri Sembilan Syariah Enactment, which criminalises cross-dressing among Muslims.
The Court of Appeal held that the section was unconstitutional and thus void. This decision was overturned by the Federal Court, less than a year later.
In a separate case, the High Court in Kuala Lumpur ruled in August 2016 that a transgender man could have his gender changed to male on his identification card.
The judge ruled that the applicant had a constitutional right to live with dignity as a male and should thus be legally accorded judicial recognition as a male. However, in January this year, the Court of Appeal overturned this verdict.
A transgender woman speaks to Humans of Kuala Lumpur about her living experience:
"Society does not have issues with me being a transwoman. Unless I dress sexily, or flirt outrageously, then I am creating problems in society but if most of us blend in and mingle freely with everyone, then it shouldn’t really be an issue.
"I have to take female hormones because I want to be a woman. I already am mentally - and that is where gender is located.
"Gender is not located in between your legs… Even for transmen, those who are female and become male (physically) have to take testosterone.
"They have beards and the butt will shrink - some do a mastectomy and remove their breasts too.
"When I produce my identity card my name will be Ali bin Abu (not her real name), yet I am like this (female-looking).
"When they call me Encik Ali, I present myself and they ask me, 'Is this you?', because the name here says Ali bin Abu, and a male.
"Gender is a concept that is fluid and cannot be dictated by what is between your legs.
"I am proudly a woman and I believe that people should call you as you wish to be called, even if your identity card says otherwise."
This story was first published on the HUMANS OF KUALA LUMPUR Facebook page. In this photography project, Mushamir Mustafa takes pictures of random people in Kuala Lumpur, who tell him a story from their lives. It features on Malaysiakini every weekend.