Historically confirmed mass infanticides

In some South American countries, homeless children are routinely killed by death squads. Don’t think that satisfies the conditions of the OP, though.

Not only that, Herod’s slaughter of the innocents only occurs in Matthew. In Luke, Jesus is presented at the Temple, where he’s praised as the Messiah, and the family returns home to Nazareth without incident. Even traveling to Bethlehem for the purpose of some census with bizarre requirements (for which there’s no independent corroboration) strains credulity.

Why would he do this:* On another, he had a number of Pharisees executed in the same year after it was revealed that they predicted to Pheroras’ wife [Pheroras was Herod’s youngest brother and tetrarch of Perea] “that by God’s decree Herod’s throne would be taken from him, both from himself and his descendents, and the royal power would fall to her and Pheroras and to any children they might have”
*

He was crazy paranoid. Not sane. Megalomaniac.

So? there’s a huge amount of history that only occurs in Josephus or Tacticus, or…

Perhaps he wanted his own dynasty to succeed, must like Henry Tudor tossing wives aside like used kleenex, all to get a son?

If Herod died when Baby Jesus was a baby, how did he manage to have John the Baptist beheaded, presumably AFTER John baptized an adult Jesus? And for that matter, how did he manage to turn Adult Jesus over to Pilate for the purpose of getting an execution authorized.

Or was that Herod Junior? And didn’t they have a cultural bias against naming their kids after a parent?

It was indeed, Herod Antipas, born before 20BC and died c. 39AD.

As far as I know, they did not, but even if they did a cultural bias isn’t the same as a cultural ban.

No, Macrobius was repeating a joke relating to Herod executing 3 of his ADULT sons in two separate incidents, after convicting them of conspiring against him. There’s no babies involved in the anecdote, or the alleged quote of Augustus. The quote is plausible, as IIRC Herod spent some time living in Rome during the turmoil in Judea, so he would have been known to high Roman society.

If you want a good assessment of who Jesus likely was and what was happening at the time, try the book “Zealot: The Life and Times of Jesus of Nazareth” by Reza Aslan.

"When it was heard that, as part of the slaughter of* boys up to two years old,…*…

italics mine.

The Mongols sometimes massacred a tribe by ‘measuring them against the lynch-pin’. What this meant, was killing every male taller than the axel of a Mongol-type cart.

What is unknown, and I think what the OP is asking about, is whether anyone has ever done the reverse - that is, ‘measured (some group) against the lynch-pin’ and killed those smaller than a certain standard.

I suspect it may have happened, in the context of slave-taking: killing of infants too small to take care of themselves or survive the rigors of slave-transportation. In short, a ruthless, heartless expedient, not as a goal on its own.

Possibly. It’s a big “maybe”, as usual with Ancient history.

The practice of exposing defective children is only documented by one non-Spartan AFAIK(though he was a massive Sparta fanboy), and archeological evidence so far doesn’t confirm his allegation.
There is indeed a chasm near Sparta, and bones dating from that period were found at the bottom indicating “throw them off a cliff” was indeed a thing Spartans did to some people, but the evidence thus far points to that being a form of capital punishment for adults. No mass children boneyards unearthed so far, or any children bones at all.