From a german who has a child and is thinking about a second one: Its less about the money but more about child care. In general wages in germany are OK. Yes it is extremly hard to get rich through labor but if you have a full time job the wage is OK (underpayed maybe but no comparison to having multiple jobs in the US). The problem is, it is often impossible to find child care. It is more or less for free and thus there are few private kindergardens.