The chick is the aquarium's first Gentoo penguin to not have its gender assigned. (Sea Life London)

A penguin chick at London Aquarium, raised by lesbian penguin parents, has been revealed to be gender neutral.

Marama and Rocky hatched an egg given to them by staff after another penguin mother couldn’t handle the pressure of two babies.

The gentoo penguin chick, yet to be given a name, is now four months old and has become the first in the aquarium’s history to not be assigned a gender.

Aquarium staff decided it would more natural to allow the chick to grow into an adult as genderless, which is normal in the wild until they mature.

To identify the genderless chick and keep an eye on its health and welfare, London Aquarium has given them a purple band on their wing.

Gender neutrality in penguins is ‘completely natural’.

Graham McGrath, general manager at Sea Life London Aquarium, said: “While the decision may ruffle a few feathers, gender neutrality in humans has only recently become a widespread topic of conversation, however, it is completely natural for penguins to develop genderless identities as they grow into mature adults.

“What makes us really proud at the aquarium is the success of Sea Life London’s gentoo breeding programme and the amazing job of same-sex penguins Rocky and Marama, who took the chick under their wing and raised it as their own.”

When the couple were mums-to-be, having been together for five years, they proved to zoo staff that they were ready for their own egg by building the biggest nest in the colony.

According to Metro, McGrath said when the chick was born: “Marama and Rocky have taken to becoming parents like ducks to water – or should I say penguins.

“Caring for a newborn is tough for anyone, from the sleepless nights to the constant feeding, yet this wonderful pair of penguin parents are completely unflappable and seem to be taking it all in their stride.”

According to Sea Life London Aquarium, climate change has affected the feeding and nesting habits of gentoo penguins and they now have near-threatened status in the wild.