Willmott and Young (functionalist)
W and Y say that there have been 4 stages of the family:
Stage 1 - pre industrial family - family is the unit of production, Stage 2 - industrial family - family members become employed outside of the home,
Stage 3 - SYMMETRICAL FAMILY - similar roles within the family for husband and wife,
Stage 4 - principles of stratified diffusion - whatever the top of the stratification system does now, the bottom will eventually do, too. Lifestyles, patterns of consumption, attitudes and expectations of higher classes will filter down to those lower social classes (e.g. baby names or outfits).