I already said that I removed my mods folder. And she's neither pregnant nor an elder; that was also stated. To reiterate: She's a YA with 90+ days before turning into Adult. She and her husband did Woohoo when they were first married, but it has been over 30 game days since then (I had aging turned off), and definitely nothing since then. There are two kittens in the household besides her and her husband, and since they are KITTENS, there is no pregnancy there either.
I know that when this has happened before, at least for a couple of people it was bad CC. Other situations the players never stated whether they got it resolved or not, so we don't know. But I removed my mods folder, then resaved the game and tried again. They are standing next to a double bed; when I click on the bed itself, I get the Woohoo option but not Try for Baby.
The game is behaving as though either neither one of them has the "can impregnate" flag, or neither one has the "can be impregnated" flag. No idea why, since when I checked to see if either got inadvertently set to custom gender, both were set default.
I may try playing another random family in the game and see if I can get the option for them. At least that will tell me if the problem is with those two Sims, or if it's within the game itself.