Mr. Mehta's family

Puzzle Question: 

In Mr. Mehta's family, there are one grandfather, one grandmother, two fathers, two mothers, one father-in-law, one mother-in-law, four children, three grandchildren, one brother, two sisters, two sons, two daughters and one daughter-in-law.
How many members are there in Mr. Mehta's family? Give minimal possible answer.

Toughness: 
Intermediate