A bit confused by your referencing senescence, since that's just growing old. Everyone is born with a fatal disease: mortality. The first and second questions

A bit confused by your referencing senescence, since that's just growing old. Everyone is born with a fatal disease: mortality. The first and second questions asked in the grandparent's post can therefore be seen as similar, which, from a purely logical standpoint, should have similar answers. However, most people would say that it is not ethical to pass a specific fatal disease to your child, but that it is ethical to have a child at all, even knowing that it will die eventually.