There are a number of accusations against God about Him killing children. Sometimes it's a broad accusation that because God is sovereign, children cannot die outside His will, and thus because children die, God is therefore a child killer. Sometimes it's a more specific accusation, such as citing a time in the Bible where God specifically commanded the extermination of entire cities, women and children included. Sometimes it's the number of children that would have died in the flood. There are even some atheists who argue that because the Psalmist who wrote Psalm 139 said he wanted Babylon's infants to be dashed against the rocks, therefore God must think it's ok to run around murdering babies.
Accusations of God killing children, directly or indirectly, are varied in their legitimacy. Some of them are taken wildly out of context, whereas others genuinely suggest that God intentionally ends the lives of children. God, as the author of life, has the authority and ability to end life at any point He chooses.
But that isn't the topic of this particular article. For now, I want to point out the hypocrisy in that those who make this objection very often support infanticide themselves. Richard Dawkins, for example, is a huge proponent of the evil God argument. Yet he believes very strongly in abortion, even to the point where he advises women who are pregnant with Down syndrome babies to "abort it and try again".
The irony of an abortionist pointing the finger at God for killing children, whether they take a verse out of context or genuinely point to an example of God killing children, should not escape anyone. Clearly, Richard Dawkins has no problem with killing children, because he, himself, supports killing children.
The more experienced among you will probably spot a flaw in my argument here. Under normal circumstances, I would have just committed what is known as the tu quoque fallacy, or as I like to call it, the "you did it too!" fallacy. Let me explain why I am not committing this fallacy.
It shouldn't surprise you to hear that there is a pretty big difference between Richard Dawkins and God. For starters, God is real, but I don't believe in Richard Dawkins. Jokes aside, there is an astronomical difference between the nature, authority, and motivation of both God and Richard Dawkins.
Nature
In nature, God is subsistent. That means he doesn't rely on anything else. He exists on His own. Furthermore, He is omniscient and omnipotent. God's omniscience means He knows the outcome of every possible scenario. He knows, therefore, when to create and end life in order to achieve His end goal. God's omnipotence means He has the power to do this. He can create life on a whim.
Dawkins lacks these attributes. He is not subsistent, he is fully dependent on God for everything, even if he refuses to acknowledge this fact. He could not choose the circumstances of his birth, he cannot prevent his own inevitable death. The resources he relies on for his continued existence are also under God's control. God could easily blight the land on which Dawkins walks, or even afflict Dawkins himself. God could cause a famine, a drought, an outbreak, a disaster, whatever He wants, and Dawkins wouldn't stand a chance. Aside from relying on God to exist, Dawkins also cannot create life. He can use himself as the vessel by which God creates life (using the reproductive mechanism created by God), but even with all our re-arrangements of God's creation, we still can't create life ex nihilo.
Furthermore, Dawkins doesn't know the outcome of specific scenarios. This is further demonstrated by his hatred of Down syndrome babies. He believes Down syndrome patients cannot have a high quality of life, so it's better to just kill them, yet many Down syndrome patients lead full lives, and despise discriminate views like Dawkins' own. To quote Frank Stephens, who testified before Congress in October 2017 regarding the life quality of people with down syndrome, "I don't feel I should have to justify my existence". Personally, I am of the opinion that abortionists should have to stand on a stage in front of a crowd of disabled people and explain to them exactly why, in the abortionist's mind, these people do not have the right to live. For bonus points, abortionists should have to explain why their own lives are more valuable.
Authority
Did your parents ever tell you "you live under my roof, you obey my rules"? Mine certainly did, and of course I was a bit of a brat, so I disagreed with that statement quite vehemently. But as an adult, I see that they had a point. What right did I have to mess the place up? It's not my house, it's their house, and I was living there rent free, with all my food bought and paid for, and luxuries pouring from my ears, what right did I have to disobey? The thing is, I had an option Dawkins doesn't. If a person wants to escape their parents authority, they can wait until they're old enough, then move. Suddenly, it becomes my house, my rules. But can a human being leave God's "roof"? There is no other place in which you can live. You will always depend on God for your very ability to breathe.
Dawkins, therefore, still lives under the authority of God. God says "you shall not murder" (i.e. take a life without due cause). This doesn't mean God Himself cannot take a life, of course. As with many things in life, it is a case of "do what I say, not what I do". It is just a fact of life that the owner of a property has more authority over it than those who do not own it. Take, for example, the phone on which I originally wrote this post. There is nothing inherently immoral about destroying a phone. There is also nothing inherently immoral about me destroying that phone. It's my phone. But if you were to destroy my phone, I could have you charged with criminal damage. Notice also how I can have you arrested, but I cannot arrest you myself. This is because I am not a police officer. If I "arrest" you, that's called assault and battery, as well as kidnapping/false imprisonment. But if a police officer arrests you for a crime, that is an arrest. Notice the exact same act has completely different moral implications depending on who commits it and why. For a human to kill a baby via abortion is murder.
However, as we've already established, God gives life. Therefore, He owns life. For God to kill is not immoral because it's His life to take. Dawkins cannot create life, therefore it is not his to take.
Motivation
Furthermore, the motivation of killing is different between God and man. God, as the author of life, is actually rather keen to sustain it. He hates death, both from an earthly perspective and from eternity. The Bible tells us that death is an enemy, the penalty for sin, and that God would much prefer the wicked turn from their sin and live. After this world dies, death will never exist again. In Heaven (where all children inevitably must go due to their incapacity to sin), death will never exist again. God hates death and loves life. Therefore, if death happens at all, it is tragic means to a glorious end.
But what about Dawkins? We've already established that Dawkins doesn't know the end of every possible scenario, and thus if abortion is means to an end for him, it is a very misguided means to an end that may not even occur. However, in Dawkins worldview, there is no good and evil anyway. There is "nothing but blind, pitiless indifference". (1) So, if Dawkins believes in an end goal, it's a very subjective end goal that differs greatly from God's end goal. To sum that up, God's motivation for killing is the well informed inevitable realisation of an objectively good goal. Dawkins' motivation is the ill informed potential realisation of a completely arbitrary end goal that he has no right to make, or guarantee of the intended outcome.
The conclusion of all of this is that if you believe in abortion, it is inconsistent to accuse God of killing children. As if you even had the right to accuse Him in the first place. As a human being, Dawkins doesn't judge God, God judges him. And He judges you too.
References
1. Dawkins, Richard - River out of Eden, Weidenfeld and Nicolswi, Chapter 4, 1995