SEPTEMBER: It must be very difficult.September never got a chance to explain since it was at that moment he decided to zap Peter with his magical airwave gun, but that line certainly left audiences wondering about the credibility of a certain rumor that's cropped up in the lead-up to the episode.
SEPTEMBER: Being a father
That rumor: is Altlivia pregnant? We know she and Peter slept together multiple times, and at the risk of being crude, there's no real way of knowing whether contraceptives were used. It's entirely plausible that Altlivia is pregnant as a result of one of these encounters, and having Peter's baby in the alternate universe could undeniably be a major aspect of Walternate's plan to take his revenge on this side.
The confirmation that this quote could bring is also strengthened by Jasika Nicole, who stated in a recent interview with TV Guide that "The biggest tease that I can offer you is that this love affair between Peter and Olivia, which involved another Olivia (from an alternate universe), has not ended. You're going to get your first hint about what it means in the first episode back, at the very end. And if you blink you'll miss it."
Now, she could be talking about that tender moment between Olivia and Peter shortly before Peter choked on the milk (that is what happened, right?). But a more blink-and-you'll-miss-it moment is - you guessed it - that very exchange between Peter and September.