The Islamic State and other Muslim, jihad groups follow Muhammad's example. Yet they kill women and young children, as seen in the Egypt bus attack in which 28 Coptic Christians were killed, and in the Manchester jihad bombing. In both instances children as young as eight years old were among the victims.
The Religion of Peace website has a helpful section that debunks Muslim myths about Islam and Muhammad which we are fed after each deadly Muslim jihad attack.
Myths of Muhammad, The Religion of Peace:
The Myth: Muhammad Would Never Do Harm to a Child
"Our Prophet (peace be upon him) was a great man who would never order any measure that might do harm to an innocent child."
It is probably fair to say that Muhammad did not approve of killing children intentionally. A verse from the Quran laments the pre-Islamic Arab practice of infanticide against baby girls, for example. Other evidence from the Hadith suggests that he instructed his men not to kill children in battle if it could be avoided, but to capture them for slavery.
He also gave children a reprieve, when telling his people to "kill those who disbelieve in Allah":
[Muhammad said] “Fight everyone in the way of Allah and kill those who disbelieve in Allah. Do not be deceitful with the spoils; do not be treacherous, nor mutilate nor kill children.” (Ibn Ishaq/Hisham 992)
But Muhammad’s definition of a child was not the same as contemporary understanding. Following the surrender of the Qurayza stronghold, he ordered the execution of every male child who had reached puberty. His men had the boys drop their pants so that that anyone with pubic hair could be beheaded (Abu Dawud 4390).