It appears most people look at this thread as ironic in a way. However, when playing through the first act of the game I have encountered two different scenarios where Tiefling children are killed or at the very least can be killed. In one instance, a Tiefling child can be killed by the druids, while an additional can be killed by harpies not far from the previous location.
For the goblin children they can be killed by the druid in his bear form when he knocks down the gate, but they also have an opportunity to run away through the main doors. I do not recall the Tiefling children being afforded this opportunity with the exception of multiple game reloads in order to get the proper rolls or setup.
Regardless, the children on both sides can be killed, it may not be the exact way you would like to kill them or have them killed, but it is available none the less.