There are six persons A, B, C, D, E and F. C is the sister of F. B is the brother of E's husband. D is the father of A and grandfather of F. There are two fathers, three brothers and a mother in the group. How many male members are there in the group ?

D is father of A and grandfather of F. So, A is father of F. 

Thus, D and A are the two fathers. C is the sister of F So, C is the daughter of A. 

Since there is only one mother, it is evident that E is the wife of A and hence the mother of C and F. 

So, B is brother of A There are three brothers. So, F is the brother of C. 

A, the father. is male B, the brother, is male, C, the sister, is female D, the grand-father, is male, E, the mother, is female F, the brother, is male. 

So, there are four males.