"Another couple threw the egg out of their batch. We picked it up and put it in the nest of the gay penguins," veterinarian Joachim Schöne told the German newspaper Bild of the pair's entry into parenthood. Z and Vielpunkt faithfully cared for their adopted egg for more than a month; in late April it hatched.  Since then, they've been taking care of their chick around the clock; it's still too young to feed itself, so the dads feed him fish mash, Schöne explained.

"Since the chick arrived, they have been behaving just as you would expect a heterosexual couple to do," the zoo said in a statement.

The Bremerhaven Zoo's same-sex penguin couples (there are three such pairs in residence there, all males) first made news back in 2005, according to the BBC.  At the time, the zoo announced plans to "test" the sexual orientations of the six penguins, who'd been seen engaging in mating rituals and trying to incubate rocks as if they were eggs.  Gay rights advocates were outraged when the zoo brought four new female penguins into the colony in a bid to encourage the penguins to reproduce, and the zoo later nixed the idea.  (In the zoo's defense, Humboldt penguins are classified as vulnerable to extinction, so it does make a certain amount of sense to be concerned about them reproducing.  And since Z and Vielpunkt have done just that, everyone wins!)

 Z and Vielpunkt aren't the first same-sex penguin pair to successfully care for a chick.  Another such couple were male chinstrap penguin residents of New York's Central Park Zoo named Roy and Silo.  Roy and Silo, much like the Bremerhaven penguins, were so anxious to hatch an egg that they tried incubating a rock. They were eventually given an "orphaned" fertile egg and successfully raised a female chick named Tango.

Another male penguin couple were removed from their colony in a Chinese zoo last year when they repeatedly tried to steal eggs from male-and-female pairs.  (In a rather ingenious move, they actually replaced the eggs they were stealing with rocks.)  But visitors complained when the penguins were removed, and eventually they were given two eggs of their own.  Since then, a keeper told the Daily Mail, "they've turned out to be the best parents in the whole zoo."

--Lindsay Barnett