Yes, eventually.
You see, neither of them is truly at 4 hearts...
I mean, they were handed to us right away at the start of act 2, they currently have as much depth as a kiddie pool.
They most likely will get more depth in act 3.
Then again, I can just quote Arc:
In-game reason: The reason you can't have more than one kid from each mother in the world right now is that they all contain some of your Artifact Essence mingled with your own power, and having multiples near each other would create the magical equivalent of a nuclear chain reaction. And that's just from a relatively small dosage of your power; Gwen and Chloe got a maximum blast, which is something the MC could only do because he was "unchained" at that moment. So even a single child with either of them risks a very big boom.
Mechanical reason: Gwen and Chloe have a lot of scenes and jump into other people's storylines quite a lot. Creating pregnant variants of all the renders and animations, figuring out where to lock the game (The Cupid Hunt event, for example, would have to be locked if either girl was pregnant, and how do I justify that in-game when Gwen wasn't even supposed to be around anyway?) and so on... it's just too much work. Things will become a lot more streamlined in Act Three and then stuff like Chloe & Gwen pregnancies will become possible.