7th Heaven just started its 10th season, which will include lots of surprises for its loyal fans — some good, some bad. For starters, troubled actor Jeremy London won't be returning to the WB family drama, nor will Ashlee Simpson or Rachel Blanchard. However, original cast members Barry Watson and David Gallagher are back as the prodigal Camden sons, Matt and Simon.

"We're focusing on our core family again," says creator/executive producer Brenda Hampton. "As the show gets older, you want to give people as much as you can of the thing that they watched it for. And in this case, it's the Camden family."

Watson and Gallagher both return for 11 episodes, so we'll have the opportunity to see the boys dealing with some more adult situations. In fact, Simon "will be the first Camden to have sex outside of marriage." Pretty risqué for the son of a preacher man!

The big story this season will revolve around Tyler Hoechlin, who joined the cast last season as Martin, a teen who's living with the Camdens while his father serves in Iraq. "We want to address people who don't have a family," Hampton says. "So one of the big pushes this year will be to talk about if you've ever thought about adoption, if you can open your home and your heart to a child, please do so."

In addition to welcoming Martin into the family, Lucy (Beverley Mitchell) and Kevin (George Stults) are preparing for the birth of their first child. "He's cool and calm and collected before the baby and she's a little nuts. And then they trade off." By the way, Hampton says Lucy's taking over as associate pastor from Chandler (London), who has "moved on."

Speaking of which, don't look for sexpot Jessica Biel to return to her roots as eldest Camden daughter Mary. "She's a very busy young woman with all her film commitments," Hampton laments. "We don't always have the people we need." Not to worry, we'd say it's a pretty full house as is.

For more dish on your returning favorites this fall, pick up the new issue of TV Guide, on sale Thursday.