According to this new science, known as epigenetics, your ancestors’ diet, smoking habits, exposure to pollutants and levels of obesity could be affecting you today. In turn, your lifestyle could affect your children and grandchildren. For Zwart and millions of others choosing to delay parenthood this raises new moral questions. What effect, for example, will nights spent in wine bars have on their descendants? Will cigarettes smoked today compromise the health of grandchildren? If they become obese is that their right, or does it impose a burden of ill-health on generations yet unborn?

Some of the answers may be emerging. There is, for example, evidence that the recent surge in diseases such as diabetes, obesity and heart disease is partly linked to the lifestyles of past generations.

Steve Jones, professor of genetics at University College London, said: “The evidence is increasingly that environmental factors like diet or stress can affect organisms in ways that are transmitted to offspring without any changes to DNA.”

As individuals we're merely links in a long evolutionary chain of past and future generations. If we live passive, unhealthy lives today, it will affect the lives our descendants. This means it's important to think about what you eat, how much you exercise, and how you spend your free time. Even further, we can't go on living the modern lifestyle of "me, me, me," without taking the larger picture into consideration. How we live today will have an impact on the future. That's powerful and important knowledge, and therefore you ought to use that to change your life for the better. Every great change starts from within yourself.