"What do you mean female?" Jon asks.
"Well your pelt is female, so I though, but it seems like you are one of the unlucky ones" the seal says.
"Unlucky?" he asks
"Some of us selkies got a pelt of the opposite sex." says the seal.
"I'm a girl? "
"For now only when you are in seal form."
"For now?" Jon asks.
"The longer you are in seal form the more female your human form becomes. And your seal will take over if you do not let her swim in the ocean every day. But that small amount of time will be fine.
The biggest problem for you is if you miss a day. Your seal will want the time she missed and more. That will cause more changes"
Jon nods "So every day come out as a seal until she has enough? How would I know when that is?"
"Do you feel like going back to the beach?"
"No. I just want to swim for a bit. "
The seal nods "She is not ready. You will know when to head back in"
They swim around for a bit until Jon comes back to the beach and removes the pelt.
He looks over himself to see how much has changed. Apart from a small increase in his chest he has gotten off lightly.
The seal calls out to him "I will see you here tomorrow morning. Keep that pelt safe."