specific fic - Found!
I think it's AU, and possibly sam and dean were adopted or raised in a foster family. I'm pretty sure it was just sam and dean, but maybe adam was there too. Or I'm wrong about all of that part. It could have just been the Winchester family living a normal non-supernatural life.
Teenage Dean gets a girl pregnant and winds up raising his son with help from his family. There was one scene where Dean and the toddler (I don't remember the kid's name) go to visit Sam at Stanford and someone snotty woman (maybe related to Jessica?) was really rude to Dean.
It might be a story in a series. I know that's not much to go on. Thanks for any help you can give.
Found in comments.