Currently being worked on, dev mentioned that it would become a priority after this update that just dropped.
"This week I've been continuing work on 0.8 and implementing the pregnancy system.
First, a rare little personal note. As I've said before, I try to keep these dev diaries about what I've done rather than what I didn't manage to do, but sometimes things happen. This week I've had to take the same cat to the vet on four separate occasions... including today! Which is why this post is a little later than usual. I think this is finally on its way to resolving favorably, but suffice to say the whole situation did impact my progress somewhat.
That said, I've managed to end up roughly where I wanted to be with 0.8 for this month after this week of work. Pregnancy now works from beginning to end for NPCs as well as the PC, making it, technically, a complete system. Still missing are events and other fluff along the way, and I'll finish out the week working on those."
This was posted from the dev on feb 20th.