Two gay male penguins trying to become fathers have stolen the eggs of lesbian penguins in a zoo in the The Netherlands, Daily Mirror reported.

The said gay penguin couple were caught stealing the nest of other birds in Dierenpark zoo in Amersfoort, the second incident since they took another bird’s egg in November—with researchers believing it is due to their desire to become fathers.

According to zookeeper Sander Drost, the eggs they stole will not likely to hatch as female penguins need to fertilize and sit on the nest.

“Homosexuality is fairly common in penguins, but what makes this couple remarkable is that they have gotten hold of an egg,” he told RTV Utrecht.

Daily Mirror reported that same-sex couples are common in more than 450 species in nature, this is the zoo aquarium’s first gay penguin couple.