Many city-dwellers have a romanticized conception of the living world. From another perspective, some "conservation biologists" favour e.g. "". By co… - David Pearce

One should be wary of assuming that we're the folk who can properly look after ourselves, whereas our descendants, if they become genetically pre-programmed ecstatics, will get trapped in robot-serviced states of infantile dependence. For it shouldn't be forgotten that exuberantly happy people also have a fierce will to survive. They love life dearly. They take on daunting challenges against seemingly impossible odds. One of the hallmarks of many endogenous depressive states, on the other hand, is so-called behavioural despair. If one learns that apparently no amount of effort can rescue one from an aversive stimulus, then one tends to sink into a lethargic stupor. This syndrome of "learned helplessness" may persist even when the opportunity to escape from the nasty stimulus subsequently arises.

Here the question comes down to an analysis of risk-reward ratios - and our basic ethical values, themselves shaped by our evolutionary past. Lest extension of the new reproductive medicine seem too rashly experimental even to contemplate, it's worth recalling that each act of old-fashioned sexual reproduction is itself an untested genetic experiment, the outcome of random mutations and meiotic shuffling of the genetic deck, and with no happy ending to date. So just who are we to accuse of reckless gambling? As it stands, all of us are genetically predestined to grow old and die; and in the course of a lifetime, the great majority of humans will experience periods of intense psychological distress, for instance loneliness and heartache after an unhappy love affair. Our social primate biology ensures that most of us sometimes experience, to a greater or lesser degree, all manner of nasty states that were genetically adaptive in the ancestral environment e.g. jealousy, resentment, anger, and so forth. Hundreds of millions of people in the world today suffer bouts of depression; others live with chronic anxiety. One might say these phenotypes are part of what it means to be human. Worse, we pass a heritable predisposition to these horrible states on to our children.

[B]oth natural selection and the historical record offer powerful reasons for doubting the trustworthiness of our naive moral intuitions. So the possibility that human civilisation might be founded upon some monstrous evil should be taken seriously - even if the possibility seems transparently absurd at the time.