The Sea Wasp (Ryk E. Spoor)

I respond to a lot of hypotheticals by pointing out that to get me into the situation described, you'd have to change me so much that I'd become a different person whose decision-making criteria the me being asked the question has no special insight into.

At first glance, I think this is one of those questions. I'm having trouble picturing the scenario, not so much because of the bit where there are vampires as of the bit where I have children.