More than 200 people turned out yesterday to show their support for a so-called civil partnership bill that would allow same-sex couples equal marriage rights.
The supporters attended the bill's first public hearing at Chandrakasem Rajabhat University in Bangkok.
It was jointly held by the Rights and Liberties Protection Department and the House committee on Legal Affairs, Justice, and Human Rights.
If the bill becomes law, it would be the first of its kind in Thailand.
The House committee chaired by Pol Gen Viroon Phuensaen, a Pheu Thai Party-list MP, started drafting the bill a year ago after receiving a complaint from a gay male couple. The couple said they had been denied a marriage certificate.
Three more public hearings will take place at Chiang Mai University on Friday, Khon Kaen University on Feb 22 and Prince of Songkhla University on March 1, respectively.
Opinions from the public will be gathered and used to amend the bill before being proposed to the cabinet for further consideration.
If the cabinet rejects the bill, the supporters have pledged to collect 10,000 names of eligible voters or at least 20 members of the House of Representatives to forward to parliament for consideration.
The bill would give same-sex couples the same marriage rights as other couples, said Setthawut Rugsujitrat, a participant at the public hearing.
However, Mr Setthawut said getting the bill passed will be tough in this country's traditional society.
A gay man at the hearing who asked not to be named said he was pleased about the bill. He called the potential changes necessary.
"In the current situation, if my boyfriend passed away, I don't have the right to retrieve his body from the hospital," he said. "And what about our assets and properties we had bought together."
Pol Gen Viroon said marriage was still reserved for a man and a woman only.
Section 1448 of the Civil and Commercial Code says marriage can only take place between a man and a woman who are each at least 17 years old, and Section 1458 requires the consent of a man and a woman to take each other as husband and wife.
Pol Gen Viroon said the code would not be amended. Same-sex couples would be able to legally register their relationships under so-called civil partnerships if and when the draft bill becomes law.
Pol Col Narat Sawettanant, director-general of the Rights and Liberties Protection Department, said the current Civil and Commercial Code has not kept up with changing perspectives on gender diversity.
The number of same-sex relationships is increasing and many of the couples want to raise families, he said. They face the problem of not being legally certified by the state.
As a result, they lose many basic rights such as joint taxation, inheritance, family health coverage and medical decision-making, he said.
Wirat Kalayasiri, deputy chairman of the committee and Democrat MP for Songkhla, said gay couples would be eligible for all the same benefits as heterosexual couples if the bill becomes law.
The most recent version of the bill refers to "civil partners" as two persons of the same sex who register their relationship under the civil partnership law. The pair must each be at least 20 years old and at least one of them must hold Thai nationality, Mr Wirat said.