Killing babies. Clearly bad, right? So why are a pair of medical ethicists claiming infanticide "should be permissible in all the cases where abortion is"? In their paper, After-birth abortion: why should the baby live? published in the Journal of Medical Ethics they argue that "the newborn and the fetus are morally equivalent" and so because we are willing to allow the mother to kill the fetus we should similarly be willing to let them kill their newborn.

Many cultures have had some form of infanticide, often by exposure [1]. The Netherlands allow it in a few cases, while many ancient cultures allowed it much more broadly. In our society, however, it is so unacceptable that the authors of the paper have been subject to intense personal attacks, even in places with normally quite sensible discussion:

You Nazi marxists at Oxford have now driven that institution to an all-time low in respect. It's you who should be retroactively aborted.

Any person who cannot understand why it is morally wrong to murder children is, quite frankly, insane. The people who wrote this article as well as your editor should be arrested for incitement to murder, and be placed in a mental hospital until such time as they can prove they are no longer a threat to our community, or our children. -- source

And:

I will say to you what I said to F. Minerva, who does not deserve to be called a "Dr" or an ethicist or anything close to the dictionary definition of what human means. You are just as evil as they for condoning and promoting such garbage. -- source

The journal editor wrote that the right response would be for critics to make "a robust academic reply to the paper", and they got several.

A strong argument for abortion is that it's very harmful to force people to carry children against their will, but this objection disappears once the child is born and could be adopted. The paper does address this, and strangely the other responses I've seen don't, but I think it's the weakest part. In the adoption as an alternative to after-birth abortion? section they write:

[H]owever weak the interests of actual people can be, they will always trump the alleged interest of potential people to become actual ones, because this latter interest amounts to zero. On this perspective, the interests of the actual people involved matter, and among these interests, we also need to consider the interests of the mother who might suffer psychological distress from giving her child up for adoption. Birth-mothers are often reported to experience serious psychological problems due to the inability to elaborate their loss and to cope with their grief. It is true that grief and sense of loss may accompany both abortion and after-birth abortion as well as adoption, but we cannot assume that for the birth-mother the latter is the least traumatic. For example, "those who grieve a death must accept the irreversibility of the loss, but natural mothers often dream that their child will return to them. This makes it difficult to accept the reality of the loss because they can never be quite sure whether or not it is irreversible" [2].

They write off adoption because of it is known to cause psychological distress on the part of the mother. They don't show, however, that it causes more distress than choosing to kill the child, only that it's more than when the child happens to die. And even then, is the closure that a parent would get from killing their child more valuable than its life?

[1] Leaving the baby somewhere to die. To some people it matters that you're not killing them, just withdrawing support.

[2] The authors cite: 'Robinson E. "Grief associated with the loss of children to adoption". In: Separation, reunion, reconciliation: Proceedings from The Sixth Australian Conference on Adoption 1997'