I would strongly suggest listening to Ron Moore's commentary; the guy is honest about the direcetion he is going in each episode as well as some of the broader implications in current events.
As far as the abortion issue I thought it was a brave move to touch the third rail on a science fiction television show. It's just not done. The colonies were basically independent states and subject to their own laws such as abortion. That sovereignty extended to the individual ships from the respective planets; each ship was sovereign. The girl was from the Gemini colony and subject to their religious laws; namely abortion is outlawed. She stowed-away to Galactica to get the procedure and there came the conflict.
Roslin is, by her own admission, socially liberal but she conceded Adama's point that they needed every body they could get. The visual of the tote-board with the population was well done.
Also, remember Boomer was pregnant with the hybrid baby and they had already considered killing it but let it live after Baltar used its blood or emnionic fluid to save Roslin. Again, raising some contemporary issues (stem cells) and dealing them with a pragmatic sense that is never shown on television.
Staying with the allegory construct it would make sense that if the Cylons are the Muslims then the issue of birthrates is comparable. Judeo-Christian cultures' rates are in decline while Muslim's are increasing.
I didn't expect the show to be liberal or conservative but I've been pleasantly suprised in how consistent its been in dealing with stuff that's never been done before. More shows should take a lead from this one.