An odd asymmetry

Most people who deny the symmetry of pre-natal and post mortem non-existence think that pre -natal non-existence cannot be a harm but post mortem non-existence can.  But is it possible to turn this around, deny the symmetry of pre-natal and post mortem non-existence, but hold that post mortem non-existence cannot be a harm while pre-natal non-existence can.

Imagine that post mortem non-existence cannot be harmful. For example, if we accept the deprivation account of the harm of death, perhaps we think that death cannot harm a person by preventing his experiencing goods that he would have experienced had he died later because we live in a world in which a person cannot die later that he will. If there is no possibility of a person dying later than he in fact will then it is not true that he could have experienced more by dying later.

I am wondering if this might be compatible with an asymmetrical view such that pre-natal non-existence might be harmful because it deprives a person of goods he would have experienced had he been born earlier. But I’ve found it difficult to construct a scenario to illustrate this position.

Imagine a case in which it is necessary that my first child will die on 31 December 2080. Perhaps there is a huge asteroid heading for the Earth that will destroy it on that day. There is nothing that could or can be done to prevent this.

I do not yet have a child. My partner and I donate sperm and an egg which produce an in vitro zygote. We can choose to have the implantation now or in a year’s time. (Imagine that this process is unfailingly successful and that I have no other children in the meantime.) In that case, would we be doing harm to the child by waiting?

As the asteroid enters the atmosphere would the child have a reasonable complaint that she was not born a year earlier?

Here it seems that the answer will depend on whether we think that the two possibilities, namely (a) first child = (zygote implanted now + life in our family + death on 31 December 2080) and (b) first child = (zygote implanted next year + life in our family + death on 31 December 2080) , are two possible lives of the same person.

If these are two possible lives of the same person then this seems to point to a possible harm of pre -natal non-existence consistent with an asymmetry between it and post mortem non-existence.

True, this asymmetrical view would be relevant only in cases where some mechanism such as the asteroid here sets a determined time for death. And perhaps the child ought rather to complain that the asteroid has cut short her life rather than that her parents did not have her sooner. I suppose the question then is which we are inclined to think is the more contingent factor.

Is there a way of fixing the scenario so that it removes any possibility of dying later that might muddy the waters?