I'm a father of 2 young children in Berlin. We have no car (neither myself not my wife even have a driver's license) but we have a cargo-bike for taking the kids places & regular bicycles when we go alone (or when one person is riding the cargo bike and the other isn't).

They are not even electric (although sometimes I wish they were) and this is very common for urban German families. If it is impractical in US cities it is only because they were built that way.

When we have to go long distance we take trains (that often have an extra car for taking bikes with you).

In specific cases where the person does not have much use for a car in the first place...

In many places in Europe people have cars because they need to commute over long distances every day.

Dutch cities, or e.g. central Paris or central London, are not representative of the a vast number (I'd say the majority) of Europeans.

You'll have an angry mob at your door if you even think about carrying a kid on anything with less than four wheels.

I see young children being carried by a trailer behind a bicycle often in the PNW region of the US.

What. I see kids on bikes/trailers on bikes in NYC all the time.

Count the wheels ;)

I chose my words carefully. Seems like bike trailers have mostly replaced those kid seats that used to go on the backs of bikes.

I see these all the time in the more affluent areas of brooklyn. Two wheels, kids on the back.

https://cdn.shoplightspeed.com/shops/611178/files/23705435/y...

I present to you this google image search: https://www.google.com/search?q=dutch+bicycle+kids&tbm=isch

Yepp seats are extremely common now. Nearly all cargo/utility bikes have compatible racks and often feature the child seats installed.

you'll see mobs on 2 wheels in India.