After watching last night, I think I know one of the secrets that's to be revealed on Desperate Housewives. I think that Mike Delfino(the plumber) is the Zack Young's biological father.
Why it could be a possibility:
-It was revealed last night that Mary Alice and Paul took Zack from a woman in her rehab center.
-The woman in the Young's toy chest was described by Paul as being someone who tried to take Zack away.(couldn't his mother try to take him back?)
-Maybe Mike's girlfriend(? I don't know if she was his girlfriend, I'm talking about the woman he's searching for. The character played by Bob Gunton, his daughter) was pregnant with Mike's baby when she went into rehab all those years ago and gave birth to Mike's baby, Zack, formerly known as Dana.
I don't know, its a little out there, but hey, it could be true. It just popped up when they mentioned Zack was stolen.
A man is getting along on the road to wisdom when he begins to realize that his opinion is just an opinion.