So, you emphasize a completely secular and doomed to disappoint view that somehow biotech is going to make us all immortal. Good luck. But here it is Holy Thursday and no reference to the more likely Reality that there is a God who dwells within us and beyond us with this gift of immortality in the offing.  Surely, even if you don't have this faith in an afterlife yourself,  it might be honest and objective to let your child know that many live-out this hope while celebrating lives richly animated by the spiritual. Ah, the brave new world of realism. Presumably, unless we set our minds like a trap and insist that there is no real life after death, and all we can hope for is biotechnology, we are doing our children a favour. Saving them stoically from hope! What a sad, uninspiring, and dark little future to offer someone...like insisting they see everything in black and white, even though they are surrounded by colour. My bet is on the spiritual reality, however   you envisage it,