B and F are children of D.
A is grandmother of F. So, B and F represent third generation.
Now, C is the daughter-in-law of E. So, A and E form a couple and represent first generation.
A, being grandmother, is a female and so E is a male.
C is the daughter-in-law of E and D is E's son. Thus, CD is the other couple and represents
C likes black, B likes pink. Green and yellow are the preferences of a couple. So,
F likes white and D likes red.
Now, E likes white and so cannot be a lady. B is the son of D and hence a male.
There are four male members - E, D, B, F