Oh, that was the problem! I didn't realize that the way it works is "stand in appropriate tile, use item, pick off list."
I've already got a lot of kids, so it takes a bit of scrolling.
On an unrelated note, I understand why it works this way from both a narrative and mechanical standpoint, but it's pretty funny that no matter how many times you get Lilaya pregnant, and even if you take the Broodmother pill right in front of her, then put her in a mating press and announce you're going to breed her, she still lets you fuck her. You'd think after the eleventh time she pushes out a litter of a dozen imps, she'd say "no, I am not going to have sex with you."