Kathy has a sister who lives in New Jersey
If Kathy's parents treated her like Elliot did with Maureen (by grounding her to her room after sneaking out late at night), then she and Elliot wouldn't have had Maureen
Elliot recalled that his first time having sex was painful- he thought he was hurting her. Elliot knocked her up.
Kathy has a cousin who works in Central Booking
When Kathy was separated from Elliot, she lived with her mother with their children
Kathy is close with her mother in law, Bernadette; she called her when Eli was born