If you’re looking to do a Mt. Etna tour with your family, you can bring your baby (if it’s not a hot summer day) and spend time around Rifugio Sapienza if you don’t want to do any big hikes.  There are little walks you can do on the craters, and if baby needs to sleep, you can push the stroller on the pavement.  But again, avoid visiting Etna with a baby (or small child) in hot weather.