Proud Same-Sex Penguin Parents Electra and Viola Welcome Their New Baby Chick

The arrival took place at Spain's Oceanografic Aquarium in Valencia.

There is a celebration in order at Spain's Oceanografic Aquarium in Valencia, since same-sex penguins Electra and Viola recently became parents.

The romance started when both female penguins, who happen to both be "infertile" began to act in a "broody" way towards one another by "building a stone nest." A typical behavior apparently that penguins exhibit before reproduction, experts say. 

Taking note of this overt display of affection, aquarium staff acted quickly and moved a fertile egg from another couple and placed it into Electra and Viola's nest. In 38 days, the egg hatched, and Electra and Viola's baby chick was born. 

Electra and Viola aren't the first same-sex penguin couple to raise a chick. 

Last year, at London's Sea Life Centre, a chick was adopted by a pair of female penguins and raised as gender-neutral by its keepers.

According to Graham McGrath, the general manager at London's Sea Life Centre, same-sex parentage is common in penguins.

"It is completely natural for penguins to develop genderless identities as they grow into mature adults," McGrath said.

For penguins, reproduction usually begins with the construction of the nests. These nests consist of round pebbles, which can reach more than 7 inches on each side, the aquarium said.

The stones are a precious commodity for these animals and can even be part of the courtship, experts say.

During the courtship, usually initiated by the male, the male will find the smoothest pebble to present to the female.

This pebble is a gift and a symbol of his affection. 

If the female likes the gift, she will place it in the nest, and then the pair run off into the sunset together as they continue to build the pebble mound in preparation for the eggs. 

Each day, the duo takes turns sitting on the egg to keep it warm during incubation. 

At 38 days, the eggs hatch. And, in no time, 75 days to be exact, the chicks become independent and are ready to say bye, bye and flee the nest. 

The emperor and king penguins are the exception to the rule, experts say, and don't follow the stone nest-building ritual. They have their own customs. This includes laying one single egg, resting it on their feet and keeping it warm under a feathery fold of skin.