No real moral guidelines for me, but I generally try to keep everyone alive and happy. They're just very good at doing the opposite.
I butcher any animals, (but don't like making kitten mittens because I love kittens) I've written my own mod that installs gender-appropriate genitalia on each and every creature in the game (for which it would make sense biologically) just because it's hilarious when your fisherdwarves get bit on the ass by a carp. I use prisoners and elven merchants for target practice, and mercilessly overwork the labor force, and then forget everything I was doing, causing me to issue MOAR ORDERS!
I DO try to make sure married women stay out of the militia and generally out of trouble, but sometimes the kids die horribly in ways I had not foreseen (like a little girl being shot through the gut by her own mother, who was operating the ballista batteries. Oh what a gory demise...), or had predicted but couldn't afford to prevent by any practical means. Then again, they and their parents usually die ecstatic for one reason or another, so at least I gave them a decent life.
Honestly, if Toady would implement a simple, reliable method of daycare for the little buggers, we'd probably not have to admit that 60% of all casualties are children.