Well, up to a point, Lord Copper. "Small but not too small" seems to be the rule. Deliberately destroying a human being outside the uterus, no matter what benefit (for others) could conceivably be wrought from the experiment, is pretty much universally considered beyond the pale — even, say, a premature infant. But destroying a human being of precisely the same age if it remains inside the uterus bothers us — as a society — a thousand times less. Hence the (general) acceptability of abortion, and of embryonic stem cell research — there being no means of conducting such research without destroying the embryonic cell donor. Put crudely, we empathise with suffering patients, but also with prisoners or others involuntarily experimented upon, or even with babies, and so come to a rightful conclusion. We cannot do the same for the unborn infant, too small and too hidden from view. We imagine, if we think about it at all, that it cannot suffer. So the balance tips in favour of the visibly suffering patient. 

The dispassionate, objective argument, that the human embryo, though small, is still human, and individual, and alive — a living human being — gains little traction. So why is this the case now, when generation upon generation of doctors and scientists, acting wholly with the consent of society, have previously rejected any thought of the expendability or utility of the human embryo? (The World Medical Association's first Declaration of Geneva, intended to update the Hippocratic Oath, stipulated: "I will maintain the utmost respect for human life, from the time of its conception" [emphasis added].) The answer lies in part in a growing, uncontrolled fear of suffering, a loathing that sweeps aside other considerations, a pathological perception of suffering that was not shared to the same extent by our forebears. Wrapped up in this is an equally increasing sense that it is quite wrong for anyone to suffer — this is the 21st century. 

Which leads us to the other end of life and the subject of assisted dying and euthanasia, another area where "progressive" forces are gaining ground. Again, there applies a conventional and very long standing moral prohibition — any act, by any person, on any innocent person including himself, that has as its primary intention the death of that individual is always wrong. But now, in Holland, Belgium, Oregon and soon probably other US states, this prohibition too is being revoked, as assisted suicide is legalised. In Britain, too, there are repeated and apparently inexhaustible efforts to change the law. 

And again, a core argument extended in favour of changing the status quo is the prevention of suffering. Proud and brave suffering individuals make heart-rending and self-evidently compelling pleas for our support in changing a law that denies them mercy and potentially prolongs suffering.