For transwoman Nisha Ayub, the debate between nature and nurture is all too familiar, often stemming from those who seek to impose who transpeople should or should not be.

However, her personal experience has provided Nisha with clarity in this matter.

In a Facebook posting, Nisha, 37, shared for the first time how she and her sibling Saraliantra, 34, were raised separately but grew up to become transwomen.

Nisha said she hailed from a mixed-raced family of Malays and Indians where both her parents had previous marriages with non-transgender children.

"Their first marriages did not last,” she added.

When her parents married, she said her mother converted to Islam and the couple had two children, Nisha and Saraliantra.

According to Nisha, her father died when she was six.

"Things were really bad at that time as my mum was all alone and had to raise everyone.

"Eventually, she had to give my younger sibling to relatives on my father's side and I was raised by my mum's side who are Christians.

"We (the siblings) were both separated at such a young age. I only had the opportunity to meet my sibling after 13 years, when I was 19," she said.

Nisha related that the planned meeting with her sibling was an awkward proposition.

"Both siblings were so nervous to meet. I was thinking how would my younger 'brother' accept having a brother who is actually a sister.

"At the same time my younger sibling was thinking the same too," she added.

When the two met, Nisha said trepidation turned to surprise when both of them realised the other was a transwoman.

"We were both so shocked to see that both of us are actually transgender women.

"It was a huge relief for us knowing that we are not alone and the best part was we are both transwomen sisters who understand each other's situation.

"We may be different in so many ways but we are blessed that we have support from each other," she added.

NIsha stressed that for them, being transwomen was not a choice or a lifestyle but a gender identity.

"Being a transgender person is not something that we ask for or dream to be. It is just the way we are born.

"Being a transwoman or transman is not something that can be nurtured but it is nature. It is just whether we want to accept it or live our life in denial to please others.

"Now that is the choice that most transpeople have to make. I choose to live my life and not to please others," she added.

Earlier this year, US secretary of state John Kerry had presented Nisha with the International Women of Courage Award for her advocacy work for transpeople's rights.