(n) jean seams, simply put
"dude you're ripping your jeams by doing that"
The hereditary and genetic background of a person. The "Jeams" are what makes a person act a certain way.
Cory: "Why are you such a lunatic all the time?"
Paige: "It's not my fault! We got double-teamed from both sides of the family!"
Cory: "Not on my side!"
Paige: "Dude, it's in my jeams!"