“I think that if for example in your passport it says neither that you are male or female, but that you belongs to a third gender category, then you are a ‘hen',” he told Norway's state broadcaster NRK.
About 20 percent of the world population are able define themselves as something other than male or female, with Nepal in 2008 becoming the first country to bring a third gender category into its constitution.
But these sea slug eggs are delicacies for fish, crustaceans and even other adults of their own species.
“The eggs can either hatch into plankton larvae that drift off to find a suitable habitat with sufficient food sources, or they can hatch out directly into tiny sea slugs,” says Evertsen.
As the “nude” in nudibranch suggests, they are naked ‒ lacking a shell.
At first glance they might seem defenceless against famished fish.
READ ALSO: When the hunters began to remove the elk's intestines, they found that the animal had teats but also a scrotum, though no testes.
"None of us had ever seen anything like it – the vet told me this happens around three times a year, out of 100,000 elks killed in Sweden each year," said Liderfelt.
“They eat just about anything that lives on the seabed," he says.
"At first, I didn't see anything strange, it was like any other elk until we looked more closely," hunter Carl-Gustav Liderfelt, who shot the animal, told The Local after Svensk Jakt first reported the unusual story.
The 67-year-old has been hunting elk since he was a teenager, and on Saturday found the 'hermaphrodite elk' in Eksjö, Jönköping in southern Sweden.
He has another hint for anyone scouting for the creatures.
“Most of today’s divers swim around with their eyes in a sort of wide-angle modus and think they are seeing quite a lot.