OK, let's also question the idea that everyone should live in the same mega-city (or in one of 20 US mega-cities).  Density is not inherently anti-family, but density can be achieved in smaller cities and big towns, with walkable centers and neighborhoods, but only in small areas--and these are surrounded with more accessible low density and open space terrain that are also within walkable distances.  Mega-cities may be very trendy, and satisfy the agenda of politcal and economic powers, but are not the best solution for most families.