Is love from families a necessity for children to form nornal relationship?
not being an expert in developmental psychology i cant give precise information but i have recently been listen several of "the great courses" on human development and personality.

i think the consensus of modern (and a large extent of more "vintage" research) would support the idea that we need affection and the security that having a relationship with caregiver provides. (bowlbys monkeys etc). any diusruption to this kind of input will have an affect on development. i did read an interesting study (i think it was an Italian university) on the development of psychopathic traits in abused children, so i think its probably safe to say that the trend certainly lies in the direction that says forming relationships needs some reciprocal affection.

i wouldnt go as far as to say that authoritarian parents  = less love-capable offspring, people are to complex for such a basic interpretation. there is also the issue of CBT and other treatments in helping to develop these bonds. i think most parents would probably agree that they didnt really know as much about love as they thought until they had children to care for.