The egg was vulnerable and helpless, abandoned by its parents and in need of warmth to survive. So officials at a German zoo gave it to a pair of gay male Humboldt penguins, named Z and Vielpunkt, who took it in and nestled it until it hatched in May. Now, the pair is happily raising the four-week-old chick.

"Z and Vielpunkt, both males, gladly accepted their 'Easter gift' and got straight down to raising it," said a zoo statement.

"Since the chick arrived, they have been behaving just as you would expect a heterosexual couple to do. The two happy fathers spend their days attentively protecting, caring for and feeding their adopted offspring."

Z and Vielpunkt aren’t the first of their kind, or even the only gay penguins at the zoo in Bremerhaven, northern Germany. In 2005, three pairs of male penguins had been seen at the zoo trying to mate and sitting on stones in lieu of eggs. It was also reported last fall that a pair of male penguins at a zoo in China was stealing eggs from heterosexual penguin couples.

Other famous gay penguin couples include Roy and Silo, the Central Park Zoo pair that inspired the book And Tango Makes Three.

Homosexuality has been documented in a range of animal species, but has not been studied in-depth.

"Homosexuality is nothing unusual among animals," Bremerhaven zoo said on Wednesday.

"Sex and coupling up in our world do not necessarily have anything to do with reproduction."