Moreover, there are very few day cares that accept children after three months (which is pretty normal in The Netherlands and probably most other Western countries). This creates the perception of having to choose between a career and children (in some fields, leaving for a few years is a high-impact career choice). Luckily, things seem to be changing slowly:

http://www.spiegel.de/international/germany/law-goes-into-ef...

There are tax incentives to have children (e.g. we wouldn't lose much income if my wife decided to stop working), unfortunately it seems that the conservative government (CDU/CSU) does not seem to be realize that most modern people don't want to live the 'man works, wife stays home with the children until they are 18'-lifestyle.

Another problem is that employers are not very flexible towards reducing the work week. Fortunately, our employer was flexible, allowing my wife to work four days. But I hear that it's hard in general for e.g. husband & wife to both work four days.