Numb3rs fanfic with a gender-swapped Charlie. She's told her father Alan than she's pregnant, and that the father doesn't know yet because he's 'out doing fieldwork' and she can't reach him to talk to him privately; she doesn't know how long it will be before he's back. She won't tell her dad who the father is, but does let slip that the man is someone she met at work. Alan assumes, due to the combination of 'met at work' and 'fieldwork' that she's talking about some sort of scientist she met at CalSci (a fictional CalTech clone).
Knowing what kinds of sciences are taught there, Alan is going to make some informed guesses as to what field the man is probably in; he will later pass on to Don (his son and Charlie's brother) that Charlie's been seeing someone, and that he (Alan) think's he's an X, or maybe a Y (marine biologist or vulcanologist? Geophysicist or systems biologist?) Alan is familiar with what is taught at the university, so he could make fairly good educated guess. Charlie has actually been quietly seeing Ian Edgerton, an FBI sniper and tracker who is currently hunting someone out in an unspecified wilderness area, but she does not want to tell that to her pacificst father until she's had a chance to speak with Ian.