Five of the six teen dramas began with main characters who were siblings or would become siblings.
On Beverly Hills 90210 we have twins Brenda and Brandon, while on 90210 there’s Annie and her adopted brother Dixon. The original also had Kelly and David as step-siblings while the new show made Annie and Dixon share a half-sibling with Naomi.
On The O.C., Seth found a brother in Ryan when the Cohens became his guardian.
One Tree Hill has half-brothers Lucas and Nathan.
And Gossip Girl has Dan and Jenny as well as Serena and Eric, along with quite a few pairs of step-siblings, some involving Chuck (with Serena and Eric) and Blair (with non-main character Aaron). And, of course, Dan and Jenny became step-siblings with Serena and Eric.
The lone exception is Dawson’s Creek. No original main characters as siblings in Capeside.
But DC is one of four teen dramas that introduced a baby sibling when the first child, the main character, was in high school or older.
On BH90210, Kelly was between her junior and senior years of high school while David was between his sophomore and junior years when they got a baby half-sister, Erin, now known on 90210 as Silver.
Dawson was a senior in high school when his parents had Lily.
Seth and Ryan were out of high school when the Cohens had Sophie.
Lucas was graduating high school when his mom had a baby girl, also named Lily.
Remains to be seen whether Gossip Girl and 90210 will continue the trend!
TeenDramaWhore 
What is up with the name Lily and teen dramas? I have always thought it was weird that name is used sooo much.
It is pretty interesting, 3 out of 6 shows using it. And it’s not *that* common of a name (I don’t think). But, as we know, there’s been tons of names repeated over the years. Probably more since I did this in September: https://teendramawhore.com/2009/09/24/fun-fact-7/
Lily’s an incredibley popular name over in the UK. Nobody ever gets a baby brother in Teen Dramas, always little girls.
Thanks for the info, Kelly! Yep, 4 baby siblings and all girls. Curious to see if and what GG and 90210 do.
I think the name Sophie for The OC was adorable! Too bad they didn’t continue.
Also, I think the CW/WB likes using the name Lily. I know it’s not a teen drama, but Veronica Mars also had a character named Lily.
Sophie was actually the name of Sandy’s mom. That’s why they picked it. (Though it’s odd since she was still alive and usually, in the Jewish religion, you don’t name someone after a person who is still living.)
Interesting theory, Kate! But I’m not sure how much say the networks have in character names, especially if the characters aren’t main ones. May just be a coincidence for all of them!
they use Nate a lot too….