Warning: SPOILERS ahead for House of Cards season 6
House of Cards season 6 reveals a surprising development as it moves into its final episodes: President Claire Underwood is pregnant! The news of the baby proves to be pivotal for the beleaguered leader, and a big jump forward in time in episode 7 finds Claire continuing to run the country and plot against her enemies while preparing to become a mother. The assumption from the nation, of course, is that Claire got pregnant with Frank's child shortly before Frank died, but the audience has reason to suspect otherwise. So, who is the father of Claire's baby: Frank, or the also-deceased writer Tom Yates, with whom Claire had an affair?
Claire herself partly answers this question - at the very least, ruling out the idea that the baby is definitely Tom's. The audience might assume so, given the rocky relationship between Claire and Frank in season 5, but in the series finale Claire has a conversation with her younger self in the baby's nursery. The young Claire comments, "What if I'm carrying a demon seed or something? The odds are 50-50" - indicating that Claire genuinely doesn't know if the baby is Frank's or Tom's. When confronted with the 50-50 odds, the adult Claire simply replies, "I'm so tired of talking about Francis."
In practical terms, it doesn't really make much of a difference who the father of Claire's baby is. Early on in the season, Claire diverted any potential rumors about her relationship with Tom by spreading a rumor of her own: that Tom was having an affair with the new White House Press Secretary. Neither of the potential fathers are still around to demand the truth, and it's hard to imagine anyone demanding a paternity test from a grieving widow who also happens to be President of the United States.
Regardless of who the father is, Claire's baby ties in with the strong themes of legacy that permeate House of Cards season 5. Doug Stamper is determined to protect Frank's legacy - so much so that he actually killed Frank in order to prevent him from killing Claire. In Doug and Claire's final confrontation, he asks her to name the baby "Frances Underwood. Frances with an E," in order to honor the man who (as far as the public is concerned) fathered her. However, given that Claire reverted to her maiden name, Hale, in an effort to distance herself from her husband (whom she's preparing to indict posthumously), we can't really see her going along with Doug's suggestion - especially since she kills him shortly after he makes it.
The fact that Claire is pregnant in House of Cards' final episode also leaves us with a rather chilling vision of the future. In season 5, Frank memorably proclaimed, "Underwood 2016, 2020, 2024, 2028, 2032, 2036," indicating that the Underwoods would defy the two-term limit - whether literally, or by manipulating things behind the scenes - to maintain power over America indefinitely. Now that Claire is about to become a mother, it wouldn't be at all surprising if she groomed her daughter to rise to power as well.