The Flying Doctors (1986) : 4x11

A new nurse, Penny, arrives as a stand-in for Kate. This upsets Maggie, since she and Penny both are from Windoona, and Penny might have a few stories to tell about Maggie. Sam and Emma lets Maggie stay with them, and Maggie tells Emma she had a son when she was very young. The father had shot through, and therefor her son David was raised as her brother. When David turned 21 Maggie told him the truth, which made him run away. There's a big cattle sale going on in the district, and DJ meets a friend called Jean, whom he only knows from radio conversations. She has a funny relationship to her stationhand Russ. She wants to have a baby with him, but he wants to marry her. They've worked out an agreement, if she gets pregnant, they will marry. In hospital Russ finds out he can't have children. He asumes Jean won't marry him because he can't give her a baby and he leaves. DJ and Jean manages to track him down and convince him to stay with Jean.