In a sign of that enduring gap, the elderly speaker called for "Mr Tanwarin" to come forward in a vote late Wednesday that saw former junta chief Prayut Chan-O-Cha elected as premier with the help of a bank of 250 appointed senators.
Tanwarin Sukkhapisit, a lawmaker for the progressive anti-junta Future Forward Party (FFP), is one of four transgender MPs in the house -- pioneers in a society where discrimination in education, employment and at home persists.
"I am not here for decoration," she told AFP. "I want to write a new political history for Thailand."
Thailand's transgender community enjoys a high profile, but still faces major hurdles in the conservative Buddhist-majority kingdom.
Transgender people in Thailand appear in commercials, movies, on the front pages of fashion magazines and even have their own beauty contest, Miss Tiffany, watched annually by more than ten million viewers.
But the media leans heavily on caricatures of the community as catty, bawdy figures -- while transgender people are often passed over for jobs as teachers and civil servants and confined to entertainment gigs and sex work.
"Thai people accept the community but don't see them as equal or entitled to equal rights," Tanwarin said.
- 'Offending good morals' -
Tanwarin's political ambitions came after a successful career as a film director.
One of her movies, "Insects in the Backyard", was released in 2010 and shown abroad.
But it was censored by Thai courts for "offending good morals".
It was only after a five-year legal battle and the removal of a three-second nudity scene that the feature film was broadcast in the kingdom.
But Tanwarin -- who is now directing a play called "Trans, I Am" -- said an artistic career was not enough to push for changes to the legal framework governing life for the LGBT community.
"We had to go into politics," Tanwarin says.
Tanwarin's first push in parliament is to change the legal definition of a married couple to "person to person" instead of "man to woman", which could lead to Thailand becoming the second place in Asia after Taiwan to allow gay marriage.
A same sex marriage bill has been floated in Thailand but it has drifted with the political turmoil and it does not give same sex couples rights to have children or adopt.
Political action is needed as the laissez-faire attitude of Thailand towards its LGBT community hides a more nuanced reality, rights groups say.
Transgender people "are regularly discriminated against in their jobs, forcing many of them into low-paid jobs," says Kyle Knight, LGBT specialist for Human Rights Watch.
Many face rejection by their families and end up in the sex industry where they are exploited.
And the term "katoey" (a Thai word covering transgender) is still thrown around contemptuously in Thai society.
Pauline Ngarmpring, who campaigned vigorously but failed to win a seat in the March election, called political inclusion a "first step" for the LGBT community and human rights in general.
The father-of-two who used to be called Pinit and made a name in the football world said there had been flickers of progress in recent years.
"Transgender people are now working as doctors, businessmen or teachers, but they are still too few."
Tanwarin's public presence alone has already sparked important debate and sometimes "virulent" comments on social media.
She relishes the challenge.
"I'm not afraid," she said. I'm here to raise awareness for those who don't understand."