If the kids are young and only have small hands, you might want to use normal gauge strings - they'll then be under less tension and will be easier for the kids to play.

Don't *ever* give a beginner steel strings to play on - the strings will cut their fingertips to shreds. Doubly so for kids, who'll have thinner skin on their hands. Much better to start with nylon strings - these will still be a bit painful on the fingers after playing for a while, but they won't actually damage the kids' fingers unless they're playing for like hours at a time.

Graham.