I don't know what it is, but more CW stars celebrate their birthday in July than during any other month. In fact, almost every CW show is represented by at least one July birthday boy or girl.

Sophia Bush (One Tree Hill's Brooke Davis) turned 27 on July 8th.

Michael Rosenbaum (Smallville's Lex Luthor) will turn 37 tomorrow, July 11th.

Steven R. McQueen (soon to be seen as Jeremy Gilbert on The Vampire Diaries) will celebrate his 21st birthday on July 13th. Steven is the grandson of Steve McQueen and the son of Chad McQueen.

Tristan Wilds (90210's Dixon) and Brian Austin Green (Smallville's John Corben/Metallo) share a birthday. On July 15th, Tristan makes it to the big 2-0, while Brian will be 36.

On July 16th, 90210's AnnaLynne McCord (Naomi Clark) will be 22.

Gossip Girl's Chace Crawford (Nate Archibald) shares a July 18th birthday with the Gossip Girl herself, Kristen Bell. If they dated, she would be the older woman in the relationship. Kristen will be 29, while Chace turns 24.

Supernatural's Jared Padalecki (Sam Winchester) will be 27 on July 19th.

90210's Rob Estes (Harry Wilson) will be 46 on July 22nd.

New Brunswick, NJ's Paul Wesley (soon to be seen as Stefan Salvatore in The Vampire Diaries) celebrates his 27th birthday on July 23rd.

Iowa girl Laura Leighton (Sydney Andrews on Melrose Place) will be 41 on July 24th.

James Lafferty (One Tree Hill's Nathan Scott) will be 24 on July 25th.

Gossip Girl's Taylor Momsen (Jenny Humphrey) turns sweet-16 on July 26th.

Did you know that Lori Loughlin (90210's Debbie Wilson) was born in Queens, NY and will celebrate her 45th birthday on July 28th?

...and last, but certainly not least, Smallville's Allison Mack (Chloe Sullivan) will be 27 on July 29th!

Mark your calendars and send 'em a card. They'll be glad you did!