However, it seems to me that the obvious reason why a "genocide of infants" would be fully a "genocide" is because human infants have the potential to become human adults. They are the living continuation of families and cultures. And the destruction of this potential, even if you accept Singer's framing, represents a much greater damage to families and cultures than the killing of livestock. Yet this would also seem to undermine Singer's conclusion, in that an organism's potential seems relevant to its "moral worth," for lack of a better term. Otherwise, infant genocide would just be the same thing as an aggressive livestock culling, except that "it perhaps offends the victims' sentiment more." — Count Timothy von Icarus
Does the following argument somewhat capture your objection to Singer?
(A) If infants are non-persons akin to livestock and the infants potential personhood is not intrinsic to the infant's moral worth, then infant genocide and aggressive livestock culling would be morally equivalent as long as all extrinsic factors are equal (offense to families, etc.).
(B) Infant genocide and aggressive livestock culling are not morally equivalent when all extrinsic factors are equal.
(C) Infants are either not non-persons akin to livestock or the infants potential is intrinsic to the infants moral worth, or both.
Edit: conclusion was too strong before. Fixed for sake of validity.
I think such an argument has force if one accepts Moorean arguments. Many hold (B) with such certainty that one could argue it outweighs the plausibility of Singer's theoretical case. I'm not sure if this is exactly how you meant for your argument to be taken. Please correct me if it is incorrect.
Now, here is how Singer, or a Singer defender, could try to lower the force of your argument:
Bias. Singer would likely give debunking explanations and counter-examples for the intuitions that support (B). (B) is, in this view, without rational support. Rather, it is due to cultural and evolutionary influences that should not be trusted.
Extrinsic potential. As a utilitarian, Singer does value potential states of affairs. Preventing persons from coming into existence on a large scale as with genocide would not maximize utility. The reason why infanticide and abortion are sometimes justified fits this view. A parent may choose to delay bringing a person about via abortion or infanticide, but they are not lowering the amount of persons that would exist. In cases of genocide, this is different, and this is a relevant difference from livestock most of the time.
Emphasis. The comparison with livestock seems worse when one does not consider Singer's wider view that the treatment of non-human animals should be significantly improved. Even if Singer argues for the lower moral status of infants, which is highly counter-intuitive, it should not be taken as being meant to be a comparison to our current treatment of non-human animals which Singer vehemently opposes.
With this in mind, I think there are ways forward for those following Singer to at least temper the effect of your argument. Still, as noted before, I think your argument has force.
"Famously?" No wonder I've never heard of the guy. The underlined random assertion simply doesn't logically follow the preceding factual statement. It doesn't even seem to attempt to. So, at least for me, it doesn't ever actually reach the threshold of what constitutes "an argument". Basically, there is no "therefore" as the logic falls apart at that point so anything that comes after and is based on that non-logical assertion is akin to opinionated rambling. Yet, you seem to entertain it, which suggests perhaps I'm simply missing something. A baby does in fact have the status of personhood, legally, and socially. It's a baby person. Any disagreement of that is like saying a different ethnicity of humanity isn't a person because "I say so", at least to me. It's just another opinion. Do you disagree? — Outlander
That is an understandable reaction to Peter Singer, yet, I think you're missing some context. Singer provides far more than mere random assertions. In
Practical Ethics (2011), he spends multiple chapters building the case that leads to his views on abortion and infanticide. Personhood, as he defines it, is not synonymous with species membership, legal status, or social status. Rather, it is about moral status, and, according to Singer, species membership, legal status, and social status, are not what gives a being its moral status. Moral status is about what morally relevant capacities the individual possesses.
Also, Singer actually gives a response to the sleep-killing scenario you describe. In
Practical Ethics he writes:
To have a right to life, one must have, or at least at one time have had, the concept of having a continuing existence. Note that this formulation avoids any problems in dealing with sleeping or unconscious people; it is enough that they, at one time, have had the concept of continued life may be in their interests. (Singer, 2011, p. 83)
Singer further justifies this by noting that we can have desires without them being at the front of our mind (Ibid.). I might want to buy a house, but I will only have this desire at the front of my mind when reminded of it in some way. Yet, according to Singer, I still possess that desire while unaware of it. It does not apply to a being if that being has never had a concept of having a continued existence, as Singer argues is the case for, for instance, a fetus.
The intellectual version of a cookie-cutter shock jock. Can't be insightful? Be controversial. — Outlander
He is certainly shocking and even offensive. But, rather than only caring about shock-value, I think Singer is most likely just a genuinely committed utilitarian that follows his arguments to their end, even when it sharply differs from what is deemed acceptable. I disagree with Singer on many things, but I think that he is a serious philosopher.
References
Singer, P. (2011).
Practical ethics (3rd ed.). Cambridge University Press.