Please pray for me: I’m going to be preaching three Sundays in three churches the next three months. Intimidated as I am to take to any pulpit, what really scares me is the possibility that one or more of these churches might also request a children’s sermon.
Now, you might think I’d want to read up on this kind of preaching. Instead, I’ve chosen to ignore the problem by instead busying myself with a small research question:
What’s the history of the children’s sermon?

Now, this element of worship isn’t common to all churches. The most recent study I could find (1999) surveyed congregations in the Southeast and discovered that slightly more Southern Baptist churches didn’t offer children’s sermons than did. (Such preaching was even less common among Episcopalians in that sample.)
But well over 70% of Presbyterian and Methodist congregations did include children’s sermons, which have been offered with some regularity by almost all the churches of my acquaintance. Moreover, it seems that the children’s sermon has existed in something like its current form for quite some time now. The following description (by a Baptist seminary professor) is 100 years old, but it sounds an awful lot like 2018, both in describing the timing/structure of the children’s sermon and in analyzing its problems and possibilities:
The children’s sermon is an established feature in many an order of service, the children under twelve being dismissed at its conclusion, with the hymn just preceding the regular morning sermon. With hymns and responses well chosen, and prayers framed with a view, both as to subject-matter and length, to the fact that children are participants in the service, the children’s sermon may bring to a climax a truly effective and helpful service. If so, it must be a real sermon, though a children’s sermon. Too many so-called sermons to children make use of the very same grown-up vocabulary as the ordinary sermon, while others quite fail of being sermons, or in any sense helpfully religious talks, but are rather poorly told stories. It is safe to say that if the minister can preach a real sermon to children he will have no trouble keeping the grown-up portion of his congregation awake, for his preaching will be concrete, simple, and full of movement. (Henry B. Robins, “The Religion of Childhood”)
But when and how did it take this form? In his 1983 study of this mode of preaching, Methodist minister James A. Carr suggested that a “thorough historical survey of children’s sermons in particular, and of children and preaching in general, would add significantly to our understanding of the historical context of children’s sermons in worship.”
I’ve yet to find any such survey, though Carr did cite examples from Peter Sangster’s study of the role of children in the awakenings of the 18th century. John Wesley, Rowland Hill, and other evangelical leaders preached at special children-only services (some organized by the novelist and abolitionist Hannah More), but they “failed to make it [theology] sufficiently simple, and also tended to overstress the element of fear, presumably because the innate wickedness of children would be proof against all but the fiercest thrusts of dogma.”
(Sangster also mentions the participation of children and adolescents in the Northampton revival observed by Jonathan Edwards. Most famously, Edwards reported on the conversion in 1735 of a four-year old girl named Phoebe Bartlet, who then appeared in his church “with an attention that is very extraordinary for such a child…. She seems very much to have the fear of God before her eyes, and an extraordinary dread of sinning against him….” Earlier in the century, German Pietism had inspired a remarkable children’s revival in Silesia — see Eric Swensson’s account of Die Kinderbeten in The Pietist Impulse in Christianity.)
In the 19th century, some ministers published volumes of sermons preached just for such children-only services. One of the earliest American examples (1828) came from Samuel Nott, Jr., better known as one of the first American missionaries to India. Generally, as in the case of this 1867 collection digitized by Google, these homilies were considerably longer than the brief lesson familiar to 20th and 21st century worship.
Lecturing at Yale Divinity School in 1888, the Sunday School advocate Henry Clay Trumbull lamented that “pulpit preaching is not addressed to children as children; nor are children included in the number of those to whom it is supposed, or designed to be intelligible.” Indeed, he suggested that 19th century Christian worship had completely misapplied Jesus’ words about “becoming as little children,” to the point that Matthew 18:3 had functionally been rendered to mean “Except ye push on and become as grown folks, ye shall in no wise share in the lessons about the kingdom of heaven.” The damage was enormous for Trumbull, since preachers were addressing themselves “chiefly to the comparatively hopeless minority of comparatively unimpressible adults, to the neglect of an obviously more hopeful majority of unquestionably impressible children…”

Alas, one of Trumbull’s historical examples of age-appropriate preaching is the sermon that inspired the so-called Children’s Crusade of the early 13th century:
Nor can we say that these children, thus marvelously swayed by the power of the living preacher, were not moved in the innermost depths of their spiritual being by the influences which impelled them to their acts of heroic—even though most unwise—daring and doing.
But in his own century, he observed not only a proliferation of separate children’s services in Britain and America (“a pleasant looking forward to the time when they can be advanced” to regular church attendance) but also experiments in “giving to the children a brief and distinct portion of the regular forenoon service, every Sunday morning” — sometimes with children remaining for the regular sermon and sometimes with them “then permitted to retire from the sanctuary.”
In this country, Trumbull credited an Iowan pastor named J.G. Merrill (a fellow Congregationalist, and later the president of Fisk University) with publishing “[p]erhaps the earliest collection of ‘five-minute sermons’ to children” in 1878. While he didn’t single out this kind of preaching as the only effective way of reaching children, Trumbull approvingly quoted the Scottish Presbyterian clergyman Alexander Macleod. Author of an 1872 book on Talking to the Children, Macleod had suggested in 1880 that at
every morning service, for one ten minutes out of the ninety, let the minister be in direct contact with the souls of the children. Let never a [Lord’s] day pass in which he shall not give wings to a story of God’s love, or [of] Christian life… Doing this we shall whet and keep whole the appetite of the children for the services of the sanctuary. Doing this, we shall open [to them] the windows of heaven, and give them also glimpses of the vision of God. And in that golden place, in those so consecrated minutes, we shall bring back for the children, and it may be for their parents as well, the days when Jesus spoke to his disciples in parables, and taught those children of his love, as they were able to receive his words.