I read a fic a while back that had Buffy and Spike having a baby. The only thing I remember about it is a scene where their at the doctors office and he is telling them she is pregnant. Spike is freaked out because he thinks he can't have kids because he is a vampire. Buffy asks the doctor to step out, and tells Spike to bite her. He does and he can tell the baby is his. That's all I can recall. It's killing me that I can't figure out what story this is.