Jerry Junior is the Son of Marnie and Jerry. He is born between Season 2 and Season 3.
Season 3[]
3x09
While Marnie is helping Lou cater for Ty's surprise leaving party, she asks Lou to babysit Jerry Junior while she goes out to get ingredients. Scott is surprised to see her babysit as he doesn't consider her to be the "baby type". She tries to prove she is but needs prompting to test the milk before heating it and giving it straight to Jerry Junior. She's later getting him to sleep just as Mallory barges in loudly, he stays asleep although Mallory points out that he needs changing. When Lou realises she's forgotten the ice and beers she shouts loudly waking up Jerry Junior. As she's changing him Peter arrives and helps her out before getting sent on a beer run. Marnie arrives back just as Jerry Junior's crying, Lou tells her it's typical as he was great all day. When she's again called unmaternal she lashes out and blames Jerry Junior. When Lou returns, Marnie is trying to cook and look after Jerry Junior when he starts crying, Lou offers to take him and they both look happy and content. (Broken Arrow)