A bit of an unusual issue from the parsha. Rashi on Parshas Noach 7:7 & 8:16 says that tashmish was asur during the mabul. The first Rashi says because the world was in trouble. Rashi on Mikeitz 41:50 - Yosef had two sons before the famine - is the source that tashmish is asur during famine. This last Rashi is from Taanis 11a. Rambam brings it in Taanis 3:8. If someone wasn't mekayem piryah v'rivyah this halacha doesn't apply to them. Even if someone already was mekayem perya verivya, shouldn't they have to fulfill onah? Yes - see Beis Yosef O"C 574. Shulchan Aruch mentions this halacha in 2 places: O"C 240:12 regarding famine (Rama adds any other trouble like famine, and his source is the Yerushalmi) and the second place is O"C 574, also for famine.
There is an interesting B"Y in 574 about Yocheved bas Levi being born bein hachomos - as the family of Yaakov reached Egypt. Tosfos asks: But that was during a famine, so how could she have been conceived? Either she was conceived from Leil tevilah (Drisha assumes the shevatim also kept the mitzvos); or Levi didn't have daughters so he wasn't mekayem pv"r yet. The difficulty with that answer is why didn't Yosef try to have a girl even though it was during a famine? Maybe Yosef did some midas chasidus. A third answer is maybe because they knew they had food so tashmish wasn't asur. We'd ask the same question about Yosef - there was food? So Yosef did a midas chasidus. My next question is, if it was midas chasidus, the Rambam shouldn't bring this halacha at all, because he doesn't pasken midos chasidus. Yet he does pasken this halacha? So Rambam would say it's not a midas chasidus.) B"Y says at end it's only asmachta.
Now, what about during recession? Should tashmish be asur? Probably not. Interestingly, this
point seems to be a machlokes between political democrats (refrain) & conservatives (don't refrain) from January - see this editorial from Wall Street Journal. But another report suggests the increased workforce did cause the recession. Is recession a lagging indicator that the birthrate is too high? I don't know if the poskim had an economy like ours in mind when a halacha like this was said.