Is nuclear family universal now?(briefly)

Nuclear family,in which there are couples of a male and female with one or more children,is tranditionally considered as universal as the norm of family that fits any people by functionalists and New right. Murdock believed it was an universal institution with universal functions and in1993,Gittins also provided an ideology cereal packet image of nuclear family by labelling other types of family as undesirable. Besides,according to New Right like Saunder and Morgan ,nuclear family is the bedrock of society which leads to a lot of laws and social policies to support. For example,conservative government introduced Family Law Act which says there has to be a year before divorce during which couples can have time to think of it carefully. With those laws,nuclear family spreaded quickly as universal at that time. Moreover,with the industrialisation,nuclear family was becoming more popular which can be described by Parsons using the concept "isolated nuclear family". The characteristics of it including geographic mobility,achieved status and loss of functions are consistent with the changes of industrialisation. This can be proved by Willmott and Young's researches in 1973 which shows that nuclear family was the mainstream in industrial society.
However,there are a lot of arguements. As found by Anserson from study of Preston consenus,extended family was popular at first stage of industrialisation and Willmott also said extended family is important but always held in reserve for some cricis. Nowadays,family diversity is increasing in terms of the introduction of McRae in 1999 with more single-hood,cohabitation,lone-parent family and same-sex family. It may be seen as a result of improving technology like contraception(Allan&Crow),changes of laws(like Civil Partnership),increasing status of women,changes of social values(Crokett&Tripp) and more expectation put on marriage(Fletcher&Parsons). Furthermore,this change is advocated by Postmodernists like Stacey as it satisfies the need of different people's preference. But we can not consequently say nuclear family is not universal. Although there is an increasing family diversity,nuclear family remains the dominant one which is said by functionalist-Chester that we should also consider the decreasing death rate with more old people living in extended family.