That is true and there are also stipend that allow you to cover cost of basic living. But that is not true in all European countries, such as the Netherlands.
There are not many students that raise a family at the same time or earn a income sufficient for supporting a family.
I mean, if anything this makes the point. Germany's fertility rate is 1.45 and the Netherlands' is 1.43. There is very little difference despite the change in education policy. So, extrapolating from this very little bit of data, it seems that education policy has a negligible effect on fertility rate.
There are not many students that raise a family at the same time or earn a income sufficient for supporting a family.