Never mind, I figured it out!

I just started the game with a fresh family, so the aging up process isn't going to happen for a while for either the YA or T. And there's only the two of them in the family and house, so I don't think it's that either. But thank you for noting those points.

<r>I have a young adult female sim and a teenage male sim. They have "tried for a baby" several times without any success. I have gone into both caste and sim options in Story Progression to enable young adult sims and teenage sims to flirt, go steady, marry, and get pregnant. And I have also turned...