This is probably just a random timeline issue that will never be explained or addressed, which is fine by me, but it does allow for the possibility of Cabe having a living daughter. The evidence for this theory will come from S1 E9, Rogue Element.
Rebecca, Cabe's ex-wife, mentions they haven't spoken in fifteen years after the divorce. Now divorce proceedings require contact between the two parties (as far as I know, I've never been divorced), and so at minimum they would have to have stopped contact immediately after the divorce. However, in this same episode, Rebecca says her daughter with her new husband, Joanna, is seventeen. That's a two year difference between the birth of her daughter and the last time they had contact. Rebecca may very well have been dating during the divorce, and gotten pregnant that way, but she hints in Rogue Element that she still has feelings for Cabe after all this time, and so during the divorce so soon after the death of their daughter, it's hard for me to believe that she would move on so quickly (she could but it just feels less likely).
There's not just scriptoral evidence as well. The one photo we have of Joanna (which is very blurry) also holds potential physical evidence to support this. Joanna's eyes are very hard to make out the color, but it's definitely a green or a blue, and both her mother and Cabe have blue eyes. Also, her hair is dark brown, and while we never see Rebecca's natural color (her hair is gray when we see her), Cabe's hair when he was younger was a very similar shade of brown. Rebecca's new husband, Mr. Burns, could have the same traits, but Cabe is not out of the running.
It's probably nothing and will most likely never be addressed, but it's fun to think about. So sound off in the comments with your thoughts.