Gammy's 'biological mother' defends husband despite indecent dealing conviction

An Australian woman believed to the biological mother of the IVF baby abandoned in Thailand has defended her husband after it emerged he had once been jailed for indecently dealing with a child.

The offence involved a child under the age of 13 and resulted in jail time for the man in 1998. 

"He is a good man - people make mistakes - that doesn't mean he is a bad person forever," the woman said.

Neither the woman nor her husband can be identified due to legal reasons.

The news comes as the couple continue to deny they abandoned baby Gammy, who has Down syndrome and a congenital heart defect.

The pair claim they weren't aware of his existence and deny that he is their son.

But the birth certificate for their daughter reveals she was born on the same day, to the same Thai surrogate who gave birth to Gammy. 

The surrogate, 21-year-old Thai woman Pattaramon Chanbua, told the ABC's 7.30 Report the couple asked her to abort Gammy and keep his healthy twin sister.

"I just cried because they were like my children," Ms Chanbua said. "We lived together every day, I could feel their movements, their bodies, their hearts were already beating, they were already children."

"Once I heard the word abortion I was upset and cried."

Reports that the Western Australian couple decided to leave baby Gammy with his Thai surrogate surfaced last week.

The abandonment, reportedly because of his Down syndrome, has raised questions about the surrogacy trade which is often viewed as a lucrative venture for women in poorer, developing countries.

Prime Minister Tony Abbott expressed his concern at the "incredibly sad story" and said the Government would look into the case.

Seven-month-old Gammy is now being raised by Ms Chanbua, who reportedly agreed to carry a child for an Australian couple for $16,000.

Reports said when the pregnancy developed into twins the couple, who have not been identified, took Gammy's healthy sister but not the baby boy, who also has a life-threatening heart condition.

Immigration Minister Scott Morrison labelled the the Thai street food vendor "a saint" for volunteering to care for Gammy.

"It is terrible, just absolutely horrible and heartbreaking," Mr Morrison said.

"But I have got to tell you who is an absolute hero in all of this and that is the Thai mother. She is a saint."

Gammy's surrogate mother, who agreed to carry the child so she could afford education for her older children and pay back family debts, has lashed out at the Western Australian couple's claims the surrogacy service only told them about Gammy's healthy sister.

Ms Pattharamon is now considering legal action against the couple, according to the Sydney Morning Herald.

"I am very upset that the father said like that. I really want him to come to Thailand to see me … I would like to talk with him in front of the media," she told the newspaper.