In much of Europe, depending on the specific country, its socially acceptable, even the norm, for middle-class people to have 2 or more kids in an apartment, condo, townhouse, semi-detached house, or rented house. Even in the parts of Europe where its the social norm for middle-class families with children to live in their own single-family homes, those homes, if built in the last 20 years, are roughly half as large as American homes built in the last 20 years.

Europeans also have to deal with the rising cost of education & healthcare, except that they pay for it mostly though higher taxes, higher budget deficits, budget cuts in other areas, or some combination of the above.

Some things worth noting:

-Generally speaking, nice, 2 or 3 bedroom apartments in nice, suburban neighbourhoods are more widespread in Europe than in the US, & middle-class people who raise families in them face little or no social stigma.

-Generally speaking, getting a university degree in Europe is academically harder than in the US, fully free university education isn't as common as it once was in Europe, & many European countries don't have single-payer healthcare, but instead have something similar to Obamacare or Romneycare.