Yes, but it depends on each country's legislation. Currently, only 28 countries authorize joint same-sex adoption throughout their territory. Therefore, it is necessary to consult the requirements of each State to see if marriage is an indispensable condition for adoption.
The countries most commonly used for intercountry gay adoption (Colombia, Brazil and Mexico) do not include marriage as a requirement for adoption.
Read the full article on: LGBT Adoption: Are Gays Allowed to Adopt in United States? ( 33).