The Big Bang Theory Season 12: 10 Things That Must Happen Before It Ends
2. Penny And Leonard Have A Baby
From the start of the show, it was pretty much guaranteed that Leonard and Penny were the canon couple of the entire series. Right from the offset, most storylines focused on their relationship and how it was flourishing. They got married after some hiccups, but haven't been doing much since. To be brutally honest, their relationship is almost at the bottom of the pile as Sheldon and Amy, and Howard and Bernadette all have something going for them - recent marriage and a newborn son respectively.
It'd be good to see the pair get one last major story arc, then, and that should be them having a child. It awards a whole new dynamic to their relationship and seeing as they do often bicker about some things, it could bring them that bit closer together. Plus, it gives someone for Halley and Neil to go on playdates with.
Seeing as Neil Wolowitz was only just born in the previous season, TBBT producers should wait until the final episode to have Leonard and Penny's baby added to the equation so it doesn't feel rushed. It would be the perfect climax to their relationship, and the show as a whole.