DW: A few years ago, Germany was fearing a population collapse. Was that just typical German angst?

James Vaupel: Yes, it was mostly German angst. But not just German angst. People in Italy, Poland or Russia are concerned about population collapse as well. The population has started to decline in many countries. And if you extrapolate this into the distant future you can imagine the situation with a much smaller population. But it takes a long time. And over a period of many decades, public policies might change, people's attitudes might change.

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Has that happened recently in Germany? We have seen a sort of mini baby boom lately.

If people had the number of children they want to have, then the typical German family would have more than two children. But the number is still much lower. Why? One problem is daycare. Another problem is combining employment with having a family. In [the former] West Germany, mothers are typically expected to stay home with small children. That is damaging for their career and their income.

The government has been trying to tackle these issues. More daycare centers, longer parental leave - has that not had any impact?

It has had a modest impact. But it is too little. When a young couple has a child, an enormous burden is put on the couple. And the government could do a lot of things to make that burden less. Denmark and Sweden, for example, do a much better job in helping young people have children than Germany does. In Denmark, there is long paternity and maternity leave. There is flextime so that people can work a flexible number of hours per week. There are a lot of part-time work opportunities. And there is lots of daycare at a very low cost.

How would you rate German policies - are we just OECD average, then?

I think Germany is below average in terms of the help provided to young people. And Germany is certainly below average in the attitude that women with children should not work. In most countries it was like that 50 years ago but not today. That is just very detrimental to fertility.

Is it up to refugees from Syria and other places then to fill the gap?

Of course, a 20-year-old migrant can replace a baby that was not born 20 years ago. The difficulty with migrants is that it is very difficult to assimilate them. This is a major problem in many European countries.

If you could change policies in Germany, what would you change first?

The pension system. The age of retirement. One of the reasons why Germany doesn't have enough money to spend on helping families is that so much money is being spent on older people who do not work. If people worked longer, that would save a lot of money and would contribute to the economy. Germany could then spend more money on education, on health, on assimilating migrants, on defense, on research, if older people worked to a higher age.

And how would you convince people to keep working?

A very important thing would be to have more flexible working hours. If you want to encourage older people to stay in the workforce you need more part-time jobs, more flextime jobs, where you can pick the hours you want to work. There is still too much inflexibility in the German system.

Dr. James W. Vaupel is the founding Director of the Max Planck Institute for Demographic Research in Rostock, Germany.