Dad , you keep talking about family in New Zealand . Who are they ?   Well , that's your uncle Bill , his wife and two of their daughters .   Is uncle Bill your brother ?   No , your uncle Jack is my brother , Bill is my brother-in-law , your mom's brother .   So his two daughters are my cousins ?   That's right , Sarah and Jane are both your cousins although they are step-sisters .   What are step-sisters ?   Sarah is your uncle Bill's older daughter . When she was young , Bill's first wife , Sarah's mom died . Three years later Bill married again .   So uncle Bill's wife is Jane's mother but not Sarah's mother . Right ?   Yes . She is Sarah's step-mother .   And when are they coming to visit us ?   They want to travel to Europe next year , and will visit us at the same Ae . 