Ingolf Baur: Scientists have seen that these environmental hormones and these environmental active substances actually have a strong effect, a strong impact on animals, but what about us humans?"

Andreas Gies: Well, we see some effects on animals, for example effects on reproduction or effects on the development of organs. And we see similar, or the same effects within the population in Germany. For example, we know that endocrine distruptors -- environmental hormones -- can disturb spermiogenesis, the making of sperm within your testis. And we see that in Germany the quality of sperm has decreased during last 20 years. It has decreased from 120 million sperms per milliliter twenty years ago to 40 million today. And we are afraid that almost half of the people in Germany, half the men in Germany are not able to perform within reproduction as they performed 20 years ago.

But that's really frightening. And can you really prove that it's due to those environmental hormones?

Proof is always difficult, but we know that this is a fact that might disturb humans. And I think we are looking for risk factors. And, without a doubt, environmental hormones are one of the risk factors that may contribute to these effects.

Andreas Gies mentoines, that there is a new chemical legislation in the EU, that regulates hormonally active pesticides.

Hormones actually play a strong role in the development of cancer. Do these environmentally active substances maybe also interfere there?

What we see in Germany and in many other countries is that hormonal-dependent forms of cancer are increasing very steeply -- more steeply than other forms of cancer. For instance, testicular cancer and prostate cancer in men, or breast cancer in women. That's a problem. And, in animal tests, we see these forms of changes within organs that may lead to cancer in humans too.

But actually these environmentally active substances come in concentrations which are very low compared to the hormones we already have in our body. Can you explain that?

Yes, but they have an effect that is additional. It's additional to the level you have and it might disturb the hormonal balance within your body, even at very low concentrations.

What can we actually do about it? I mean, how do we get rid of these substances?

Within the European Union, I think we're one the right road. We have a new chemical legislation, REACH, which gives us the chance to regulate these substances, so we can control them better and they need an authorization. And, for example, estrogenic, or hormonally active pesticides won't be on the market for the next 6 years.

Why can't we just forbid all kinds of substances, like these plastic softeners or Bisphenol A? Why can't we just say: Let's not produce them anymore?

I think they are the backbone of our economy. And we have to look to take them on board in those fields in which they have no effects on humans, or that we control them in fields in which they are close to us or the environment.

Interview: Ingolf Baur