In order to have a child through surrogacy in Thailand, you must be a heterosexual couple who have been married for 3 or more years. At least one of the two partners must be a Thai national. It is also necessary to prove a medical incapacity to gestate. Also, future parents can only go to a voluntary surrogate if no woman close to them can gestate their baby.
With the passing of the 2015 Act, single people and gay or lesbian couples cannot access this reproductive method in Thailand without breaking the law.
Suggested for you: Surrogacy in Thailand: Legislation, Costs and Debate.