The Big Bang Theory's series finale gave Penny and Leonard a touching ending with the reveal that the couple are expecting a baby. However, the show could have done a much better job in crafting the pregnancy storyline, particularly since so much of the sitcom's final season was devoted to the couple's kid/no kid arc - which now feels somewhat redundant.
Uneven storytelling was a recurring problem especially in the latter seasons of The Big Bang Theory, with majority of the attention zeroed in on Sheldon's story. Penny and Leonard were bumped to secondary characters when they'd been an integral part of the series from the start. When the announcement that season 12 will be The Big Bang Theory's final, everyone expected the narrative to pay equal attention to all seven core characters in preparation for a proper send-off. But instead, the sitcom doubled down on its ways, spending the majority of its 24 episodes milking the Coopers' Super Asymmetry/Nobel subplot while giving the rest of the cast throwaway storylines like the Hofstadters' supposed dilemma about not having a kid.
Introduced in episode 3 wherein Penny casually revealed that she doesn't want to have kids ever, much of the Hofstadters' storyline in season 12 revolved around her and Leonard's conflicting views about starting a family. Right from the start, Leonard was always keen on having children, famously saying in The Big Bang Theory's premiere that he and Penny will have smart and beautiful babies despite having just met her. The issue was inconsistently tackled and went on odd twists and turns. At one point, they were even setting up Leonard to donate sperm to Penny's ex-boyfriend, Zack, for his new wife's baby. But in the end, it seems like none of this mattered, since Penny ended up pregnant anyway and apparently did a complete 180 on the baby issue.
To be fair, the plot point was concocted before the writers of The Big Bang Theory learned that they only have one more season left. After all, nobody expected the sitcom to end considering its high ratings, and CBS was vocal about green lighting season 13 had it not been for Jim Parsons' decision to walk away from the gig. Perhaps the plan was to properly develop the baby plot and make it an overarching story that would continue to play out in another season. This way, the show would've been able to better establish the couple's conflicting positions when it came to having kids. Leonard had been clear about wanting them, but Penny's insistence that she never wanted to have children felt like it came out of nowhere.
Despite the poorly established conflict, The Big Bang Theory moved forward with the arc set for the Hofstadters. Leonard and Penny didn't have any extensive discussions about the matter, however; Leonard simply compromised and honored his wife's choice (as he should) with very little pushback. It was important for the series to acknowledge Penny's decision to not have a baby - something that people involved in the show emphasised throughout the show's final year. Tackling her unconventional decision is pivotal in this day and age where women's rights to choose have been at the forefront of many social and even political conversations. It was The Big Bang Theory's opportunity to tackle a more serious matter, something that it rarely did in its 12-year run. Sadly, the storyline came to a weak resolution, without any proper exploration of Penny's real feelings about her accidental pregnancy.
The question is, why introduce and sit on the kid/no kid issue if it was going to be overturned at the last minute for a fan-pleasing ending? Seeing Penny pregnant and very much in love with Leonard may be a happy ending, but The Big Bang Theory could have chosen to spend its allotted time on the Hofstadters in a way that would've progressed their arc. The plot was overextended, and sometimes it felt like it was because the writers didn't know what to do with it. Many fans hated the baby conflict, but seeing Penny forced into something that she was vocal about not wanting sends the wrong message.
Instead of waiting at the very last episode of the series, The Big Bang Theory could have introduced the accidental pregnancy halfway through the season and showed us how the couple dealt with the news knowing that they have different opinions on the matter. This would've been a major plot arc in the show's final season - something that can be intercut with Sheldon and Amy's Nobel bid. The show could also have taken a bolder approach: stuck with Penny's decision to not have kids, and let the Hofstadters be a shining example that couples don't necessarily need to have children to be happy. In any case, both of these scenarios could've still led to a satisfying finale for the show's inaugural couple.
All in all, the one-hour series finale of The Big Bang Theory was full of callbacks and fan-service, which made for a very satisfying send off to the Pasadena gang. However, the show's handling of Leonard and Penny's pregnancy arc (not to mention Raj's pointless story) was bad, leading to what may seem like the perfect happily ever after for the couple, but was actually very problematic. It invalidates Penny's original stance about kids, sending the wrong message about women having a say in an issue that will impact their lives forever. Granted people can change their minds, and perhaps Penny did, but we don't know that because the show didn't address this sudden turn of events. All we saw was her go through a couple of cliche pregnancy tropes, and a bleak comment about the idea of being pregnant not fully sinking in yet.
It might seem like it's too much to ask for The Big Bang Theory to better depict Penny's choice to not have kids and the ripple effect it had on her marriage since it's a heavy subject matter given the show's nature, but it's not uncommon for sitcoms to tackle timely issues. Cheers did it with alcoholism; Full House dealt with domestic violence and body image; How I Met Your Mother discussed gun control and sexuality; and Black-ish does it almost every episode with social commentaries on race and police brutality. At the very least, The Big Bang Theory could have avoided tackling this sensitive issue altogether, rather than rushing through it and botching the execution.