One of the final episodes of the third season gave away a potential plot for Serena Joy s character.
In season 3, episode 11, Serena Joy slept with her husband just before they arrived at the Canadian border.
But upon arrival at the border, Mark Tuello (Sam Jaeger) managed to arrest them for the war crimes in Gilead. There was also a symbolism that was shown, a womb imagery with a lamp in the middle.
However, not everyone is still convinced that Fred is the dad. The fact that they re trying to make us think it s Fred s makes me think that it s not, one Redditor said.