This is a serious post and the longer it is the boring it becomes so KISSing it.
I am doing this course called Indian Social Structure. I was reading about family and relationships and felt it's thought provoking.Never in my life I gave a serious thought on family (in isolation) cos I felt it something too silly to think about and has always taken it for granted. I believe it's the same case with most of the people. I've realized how complex is a family only after doing this course. I would like to the share just the sociological definition of family and will keep it crisp, saving the rest of the globe for my exams.:)
In sociological terms a family is an institution based on the idea of compulsory hetero-sexuality. A feminist would definitely agree to the definition of Family as an arena of power struggle, uneven asymmetric distribution of power, typically the old over young, male over female. This idea resides in the concept of marriage (legitimate domain of sexuality) in Indian context.
One thing I observed in sociology, the word institution is over used. According to it marriage, family, caste, relationship...and the list doesn't end (il y a beaucoup) all are different institutions.