Answer the questions based on the information given below. Seven persons T, U, V, W, X, Y and Z are in the family of three generations. X is married to Z, who is the son of Y. X is the mother of T and mother-in-law of W. T is not married to W. V is the daughter of U's nephew. U doesn't have any brother. The gender of W, T and U is same.   How is U related to Z?