I’m thinking of a situation where a character is able to calculate an exact conception date for her pregnancy. Outside of sexual intercourse that is bookended by weeks of abstinence, this is not likely to be accurate, but in this trope it is treated as highly scientific. For instance: a woman will be asked about the parentage of her child, and she will say, “Well, the doctor says I am 7 weeks pregnant, and I had sex with Bob exactly 7 weeks ago, so it is definitely his.” (Nevermind that she slept with Bill 3 days before that, and Steve the day after)
I’ve seen this come up in fiction several times, but the only specific example I can give is from the tv series Oz, when Vern confronts his daughter-in-law about the parentage of Jewel (Vern’s granddaughter). She admits that her husband had been prostituting her, and that she had been with her husband and 2 other men on the *exact date *her daughter was conceived.
I wanted to pose this question to the tvtropes website, but am having trouble understanding how to join the community and/or pose questions. I am hoping my fellow Dopers will help me out. Thank you.
