Bangkok, May 13 (IANS): A gay couple left for Spain on Friday with their child following a long legal battle to secure custody of the baby born through surrogacy in Thailand.

"Today is a big day for our family, we just started the journey for our family to be together after 16 months," wrote the couple -- Spaniard Manuel Santos and his American partner Gordon Lake -- in a Facebook post, accompanied by a photo showing them with their daughter Carmen inside a plane.

"Tomorrow we will be with our son Alvaro in our home with our family," they added via the social media page, created as part of the campaign to win Carmen's custody.

Carmen Lake, conceived with Lake's sperm and the egg of an anonymous donor and borne by a Thai surrogate named Patidta Kusonsrang, was born on January 17, 2015, EFE news reported.

Problems surfaced when Patidta, who had signed papers at the hospital granting paternity rights to Lake, failed to appear at the US Embassy in Bangkok to finalise the necessary documentation to allow the baby to leave the country.

The couple, who have another son conceived through surrogacy over two years ago in India, failed to settle Carmen's case amicably with Patidta and filed a custody claim.

On April 26, a Thai court ruled in favour of the couple, awarding all parental rights to Lake.

However, the couple must return to Thailand for the defamation suit they filed against Patidta and her legal advisor Verutai Maneenuchanert, who they accuse of taking recourse to "lies and tricks".

"We will come back soon because we won't stop until they pay for all they have done to us," the couple asserted in the message.

Thailand's parliament enacted laws in February 2015 banning foreigners from hiring surrogate mothers.