Science and life’s inviolability Chris Barbara, from Doctors for Choice (May 6), attacks the claim that a fertilised embryo is a human person, saying this cannot be scientifically proved. He even states the opposite: “It would be more helpful to consider embryos for what they are: a precursor to a human person.” Is it a ‘scientific fact’ that they are not a human person, such that one should feel no qualms about aborting them? While it is an obvious (‘scientific’?) fact that embryos normally grow to behave as persons, there is no obvious ‘scientific’ marker of the point when personhood sets in. Personhood remains mysterious to ‘science’ but, in law and ethics, we give it great weight. For Barbara, too, the taking of personal life seems to be a red line.